Camera system having a communication system between a camera body and a photographing lens

ABSTRACT

An interchangeable lens camera system having a camera body, a photographing lens, and a rear converter, the camera body and photographing lens communicating with each other via a first group of contacts and a second group of contacts, respectively, includes a group of relay channels via which the first group of contacts are electrically connected with the second group of contacts, in a state where the rear converter is mounted between the camera body and the photographing lens; a memory in which rear converter data is stored; and a controller which reads the rear converter data from the memory. The memory and the controller have a function to send the rear converter data to the camera body while the camera body and the photographing lens communicate with each other via the first group of contacts, the second group of contacts, and the group of relay channels.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a camera system having a camera bodyand a photographing lens which is detachably attached to the camerabody, and having a communication system between the camera body and thephotographing lens, wherein a rear converter can be mounted between thecamera body and the photographing lens.

2. Description of the Related Art

In conventional interchangeable lens cameras, the camera body obtainsfundamental information on the photographing lens via predetermined datacommunication performed between the camera body and the photographinglens. However, if a rear converter is mounted between the camera bodyand the photographing lens, the data communication cannot be performed,so that it is impossible to use any useful features that thephotographing lens may possess.

Even if the rear converter is simply provided with relay channels forconnecting each communication channel of the camera body with acorresponding connecting channel of the photographing lens, the camerabody cannot recognize the existence of such rear converter, so that thecamera body cannot control operations of the photographing lens properlywith only data received from the photographing lens. In addition, if thecamera body is provided with additional electrical contacts for datacommunications between the camera body and the rear converter, thecamera body needs to be provided with one or more additional componentsfor the additional electrical contacts, and also switching between thecommunication channels becomes necessary, complicating the structure ofthe camera system.

SUMMARY OF THE INVENTION

The present invention provides a communication system between a camerabody and a photographing lens of a camera system, wherein a rearconverter can be mounted between the camera body and the photographinglens, and data on the rear converter can be used without any complicatedstructure.

For example, in an embodiment, an interchangeable lens camera systemhaving a camera body, a photographing lens, and a rear converter whichcan be mounted between the camera body and the photographing lens, isprovided, the camera body having a first group of contacts, thephotographing lens having a second group of contacts, the camera bodyand the photographing lens communicating with each other via the firstgroup of contacts and the second group of contacts with the first groupof contacts being electrically connected with the second group ofcontacts, respectively, wherein the rear converter includes a group ofrelay channels via which the first group of contacts of the camera bodyare electrically connected with the second group of contacts of thephotographing lens, respectively, in a state where the rear converter ismounted between the camera body and the photographing lens; a rearconverter memory in which rear converter data on the rear converter isstored, the rear converter memory including at least one portelectrically connected to corresponding at least one relay channel ofthe group of relay channels; and a rear converter controller whichcontrols a reading operation of the rear converter data from the rearconverter memory, the rear converter controller including at least oneport electrically connected to corresponding at least one relay channelof the group of relay channels. The rear converter memory and the rearconverter controller have a function to send the rear converter data tothe camera body while the camera body and the photographing lenscommunicate with each other via the first group of contacts, the secondgroup of contacts, and the group of relay channels.

It is desirable for the photographing lens to include a lens memory inwhich photographing lens data is stored; wherein the camera bodyincludes a body controller which communicates with the lens memory toread the photographing lens data from the lens memory; wherein a portionof the photographing lens data serves as dummy data for the rearconverter; and wherein the rear converter data is read out of the lensmemory to be transmitted to the body controller in synchronization withan operation of the body controller in which the body controllerreceives the dummy data.

The body controller can be electrically connected to the rear convertercontroller via a first communication/control contact of each of thefirst group of contacts and the second group of contacts, and a data I/Ocontact of each of the first group of contacts and the second group ofcontacts. The photographing lens can include a lens controller whichcommunicates with the body controller. The body controller iselectrically connected to the lens controller via the firstcommunication/control contact, a second communication/control contact ofeach of the first group of contacts and the second group of contacts,and at least one relay channel of the group of relay channels, wherein ahandshake operation is performed between the body controller and thelens controller via the second communication/control contact. The lenscontroller sends out dummy data to enable the data I/O contact ifinputting a command for the rear converter, which is issued by the bodycontroller, via the data I/O contact, while the lens controllercommunicates with the body controller. The rear converter sends out therear converter data to the data I/O contact in the case where thecommand is input via the data I/O contact.

In an embodiment, the rear converter receives the dummy data from thelens controller in the case where the lens controller receives thecommand; and the rear converter sends the rear converter data to thebody controller in synchronization with an operation of the bodycontroller in which the body controller receives the dummy data.

The body controller can be set to recognize one of a last one byte and alast few types of the photographing lens data as the dummy data for therear converter.

In another embodiment, a rear converter which can be mounted between acamera body and a photographing lens of an interchangeable lens camerasystem, is provided, the camera body having a first group of contacts,the photographing lens having a second group of contacts, the camerabody and the photographing lens communicating with each other via thefirst group of contacts and the second group of contacts with the firstgroup of contacts being electrically connected to the second group ofcontacts, respectively, wherein the rear converter includes a group ofrelay channels via which the first group of contacts of the camera bodyare electrically connected with the second group of contacts of thephotographing lens, respectively, in a state where the rear converter ismounted between the camera body and the photographing lens; a rearconverter memory in which rear converter data is stored, the rearconverter memory including ports electrically connected to at least onerelay channel of the group of relay channels; and a rear convertercontroller which controls a reading operation of the rear converter datafrom the rear converter memory, the rear converter controller includingports electrically connected to at least one relay channel of the groupof relay channels. The rear converter memory and the rear convertercontroller have a function to send the rear converter data to the camerabody while the camera body and the photographing lens communicate witheach other via the first group of contacts, the second group ofcontacts, and the group of relay channels.

Each of the first group of contacts and the second group of contacts caninclude a first communication/control contact via which the bodycontroller sends a control signal to the lens controller; a secondcommunication/control contact via which the lens controller sends acontrol signal to the body controller; and a data I/O contact for datacommunication. The first communication/control contact, the secondcommunication/control contact, and the data I/O contact of the firstgroup of contacts are electrically connected to the firstcommunication/control contact, the second communication/control contactand the data I/O contact of the second group of contacts, respectively,via the group of relay channels. The rear converter memory and the rearconverter controller are electrically connected to relay channels of thegroup of relay channels which correspond to the firstcommunication/control contact and the data I/O contact. The rearconverter memory and the rear converter controller have a function tosend the rear converter data to the camera body after a commencement ofa handshake operation between the body controller and the lenscontroller via the second communication/control contact in the casewhere the camera body commands the rear converter controller to send therear converter data via the data I/O contact.

The present disclosure relates to subject matter contained in JapanesePatent Application No.2001-54543 (filed on Feb. 28, 2001) which isexpressly incorporated herein by reference in its entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described below in detail with referenceto the accompanying drawings in which:

FIG. 1 is a block diagram of fundamental elements of control systems ofa camera body and a photographing lens of an SLR camera system having acommunication system between the camera body and the photographing lensaccording to the present invention;

FIG. 2 is a block diagram of fundamental elements of the control systemof the camera body;

FIG. 3 is a block diagram of fundamental elements of acommunication/control system of the photographing lens;

FIG. 4 is a block diagram of fundamental components of a photographinglens which is provided with a lens controller which operates with afirst power, and a peripheral circuit which operates with a secondpower;

FIG. 5 is a block diagram of fundamental components of a photographinglens which is provided with a lens controller and a peripheral circuitboth of which operate with the first power;

FIGS. 6A and 6B show a flow charts for the first portion of a mainprocess of the camera body, to which the present invention is applied;

FIG. 7 is a flow chart for the remaining portion of the main process ofthe camera body, to which the present invention is applied;

FIG. 8A is a flow chart for a communication identification processincluding of an old-type communication process and a new-typecommunication setting request process of the camera body;

FIG. 8B is a flow chart for operations of a photographing lens which areperformed in accordance with operations of the new-type communicationsetting request process of the camera body;

FIG. 9 is a flow chart for the new-type communication setting requestprocess of the camera body;

FIG. 10 is a flow chart for a camera state information setting processof the camera body;

FIG. 11 is a flow chart for an image-shake compensation data settingprocess of the camera body;

FIG. 12A is a block diagram of fundamental elements of a control systemof the first embodiment of the photographing lens which incorporates animage-shake compensation device;

FIG. 12B is a conceptual diagram of a compensation lens (animage-stabilizing optical system) LC of the image-shake compensationdevice;

FIG. 13 is a flow chart for a main process of the first embodiment ofthe photographing lens;

FIG. 14 is a flow chart for a new-type communication setting process ofthe photographing lens;

FIG. 15 is a flow chart for a 1 ms-timer interrupt process of the firstembodiment of the photographing lens;

FIG. 16 is a flow chart for the first half of an inverse-INT interruptprocess of the first embodiment of the photographing lens;

FIG. 17 is a flow chart for the remaining half of the inverse-INTinterrupt process of the first embodiment of the photographing lens;

FIG. 18 is a timing chart for the communication identification processfrom the moment the main switch of the camera body is turned ON to themoment immediately after the commencement of the new-type communicationprocess;

FIG. 19A is a timing chart for a handshake operation performed betweenthe camera body and the photographing lens at the commencement of thenew-type communication process;

FIG. 19B is a timing chart for a handshake operation performed betweenthe camera body and the photographing lens at the commencement of thenew-type communication process;

FIG. 20 is a timing chart for an old-type communication process that isperformed between the camera body and the photographing lens;

FIG. 21A is a timing chart for communication in the new-typecommunication process that is performed between the camera body and thephotographing lens;

FIG. 21B is a timing chart for communication in the new-typecommunication process that is performed between the camera body and thephotographing lens;

FIG. 22 is a block diagram of fundamental elements of acommunication/control system of a second embodiment of the photographinglens 200 which incorporates a lens AF system;

FIG. 23 is a flow chart for a main process of the second embodiment ofthe photographing lens;

FIG. 24 is a flow chart for a 1 ms-timer interrupt process of the secondembodiment of the photographing lens;

FIG. 25 is a flow chart for the first half of an inverse-INT interruptprocess of the second embodiment of the photographing lens;

FIG. 26 is a flow chart for the remaining half of the inverse-INTinterrupt process of the second embodiment of the photographing lens;

FIG. 27 is a schematic block diagram of fundamental elements of controlsystems of a photographing lens, a rear converter, and a camera body ofan embodiment of an SLR camera system, wherein the rear converter ismounted between the camera body and the photographing lens;

FIG. 28 is a timing chart for the communication identification process,from the moment the main switch of the camera body is turned ON to themoment immediately after the commencement of the new-type communicationprocess in the embodiment of the SLR camera system shown in FIG. 27;

FIG. 29 is a timing chart for communications in the new-typecommunication process that is performed between the camera body and thenew type of photographing lens, and between the rear converter and thecamera body in the embodiment of the SLR camera system shown in FIG. 27;

FIG. 30 is a flow chart for the main process of the rear converter;

FIG. 31 is a flow chart for the new-type communication setting processof the rear converter; and

FIG. 32 is a flow chart for the inverse-INT interrupt process of therear converter.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows fundamental elements of control systems of a camera bodyand an interchangeable photographing lens of an embodiment of an SLRcamera system to which the present invention is applied. The camera body100 is provided with a body CPU (body controller) 111 serving as acontroller which comprehensively controls the overall operations of theSLR camera system. The camera body 100 is provided with a body mount 103to which the photographing lens 200 is mounted. A group ofcommunication/control contacts (body communication line) 104 areprovided on the body mount 103. The group of communication/controlcontacts 104 consists of six contacts in this particular embodiment. Oneof the six contacts serves as a power contact (constant-voltage contact)for supplying a first power from the camera body 100 to low powerelements (e.g., a ROM) provided in the photographing lens 200 to drivethe low power elements, while another one of the six contacts serves asa control terminal via which a ROM provided in the photographing lens200 is enabled or disabled (i.e., turned ON or OFF). A power contact 105(VPZ) via which a second power is supplied from the camera body 100 tothe photographing lens 200 is provided on the body mount 103. The powercapacity of the second power that is supplied from the power contact 105(VPZ) to the photographing lens 200 is substantially greater than thatof the first power that is supplied from the aforementionedconstant-voltage contact of the group of communication/control contacts104. Although the supply voltage of the second power is greater than thesupply voltage of the first power, the supply voltage of the secondpower can be identical to the supply voltage of the first power or evensmaller than the supply voltage of the first power as long as the powercapacity of the second power is substantially greater than the powercapacity of the first power.

Although it is desirable that the group of communication/controlcontacts 104 and the power contact 105 (VPZ) be provided on the bodymount 103, the group of communication/control contacts 104 and the powercontact 105 (VPZ) can be provided behind the body mount 103 in a mirrorbox of the camera body 100, in which a quick-return mirror ispositioned. Alternatively, it is possible that the group ofcommunication/control contacts 104 be provided on the body mount 103 andthe power contact 105 (VPZ) be provided behind the body mount 103 in themirror box of the camera body 100.

FIG. 2 shows fundamental elements of the control system of the camerabody 100. A photometering switch SWS, a release switch SWR, a mainswitch SWMAIN, an image-shake compensation switch SW1 and an AF switchSWAF are connected to the body CPU 111, which serves as a controllerthat comprehensively controls the overall operations of the SLR camerasystem.

The power to peripheral circuits of the camera body 100 is turned ON andOFF when the main switch SWMAIN is turned ON and OFF, respectively. Thepower from a battery 113 accommodated in the camera body 100 is suppliedto each peripheral circuit of the camera body 100 via a regulator (DC/DCconverter) 116 when the main switch SWMAIN is turned ON, and the powerfrom the battery 113 to each peripheral circuit of the camera body 100is cut off when the main switch SWMAIN is turned OFF. The body CPU 111is always supplied with power from the battery 113 via the regulator116, so that the body CPU 111 is in operation at all times.

The camera body 100 is provided with a strobe circuit 121, a mirrorcircuit 123, a shutter circuit 125, a film-winding circuit 127, aphotometering circuit 129 and a distance measuring circuit 131, whichare all connected to the body CPU 111. The photometering switch SWS isturned ON when a release button (not shown) is the camera body isdepressed by half a step, and the release switch SWR is turned ON whenthe release button is fully depressed. Immediately after thephotometering switch SWS is turned ON, the body CPU 111 actuates thephotometering circuit 129 to perform a photometering operation. At thesame time, the body CPU 111 calculates and sets an optimum shutter speedand an optimum aperture value (f-number), and actuates the strobecircuit 121 to perform a strobe charging process as needed. Furthermore,the body CPU 111 actuates the distance measuring circuit 131 todetermine an amount of defocus, to perform an autofocus process if anautofocus mode has been set via the AF switch SWAF. Immediately afterthe release switch SWR is turned ON, the body CPU 111 actuates theshutter circuit 125 to drive a focal plane shutter mechanism (not shown)to expose a film frame. Upon completion of an exposure, the body CPU 111actuates the film-winding circuit 127 to wind up film by one frame andat the same time to charge the focal plane shutter mechanism.

When the new-type photographing lens (e.g., a KAF III type photographinglens having a lens CPU, a lens ROM, and all of the communicationfunctions which correspond with those of the camera body 100) 200 ismounted to the camera body 100, during the time the main switch SWMAINis ON, the body CPU 111 turns ON a switch circuit 115 to supply thepower from the battery 113 as the aforementioned second power to thephotographing lens 200 via the power contact 105 (VPZ) of the camerabody 100 and associated power contact 205 (VPZ) of the photographinglens 200, which is in contact with the power contact 105 (VPZ). Inaddition, if an image-shake compensation mode has been set via theimage-shake compensation switch SW1, and if the photographing lens 200is provided with an image-shake compensation device, the body CPU 111outputs an image-shake compensation command to the photographing lens200 via lens communication to make the photographing lens 200 perform animage-shake compensation operation. If the photographing lens 200mounted to the camera body 100 is further provided therein with a lensAF system, the body CPU 111 outputs defocus data (e.g., the amount ofdriving of an AF motor 261 (see FIG. 12A) and the direction of drivingof the AF motor in the photographing lens 200) to the photographing lens200 via lens communication to make the photographing lens 200 perform alens autofocus process.

As shown in FIG. 12A, an encoder 231, the AF motor (focusing lensdriving device) 261, an AF lens group (focusing lens group) Lf, and thelens CPU 211 constitute a focus adjusting system (electrical component).

The photographing lens 200 is provided on a lens mount 203 thereof witha group of communication/control contacts (lens communication line) 204and the power contact 205 (VPZ). The group of communication/controlcontacts 204 and the power contact 205 (VPZ) come into contact with thegroup of communication/control contacts 104 and the power contact 105(VPZ) of the camera body 100, respectively, when the photographing lens200 is mounted to the body mount 103 of the camera body 100 via the lensmount 203. The photographing lens 200 is provided therein with a lensCPU (LCPU/lens controller/electronic device) 211, a lens ROM (LROM/lensmemory/nonvolatile lens memory) 221, the encoder 231 and a peripheralcircuit 241. Various modes and parameters are stored in the lens ROM221. A current focal length (zoom code) and a photographic distance aredetected via the encoder 231. The peripheral circuit 241 includes, forexample, as shown in FIG. 12A, image-shake compensation motors (X-motor254 and Y-motor 257), the AF motor 261, and a power zoom motor (powerzoom driving device) 264, which are all provided in the photographinglens 200. Note that the power zoom motor 264 is connected to a lensgroup Lz, wherein the lens group Lf and the lens group Lz constitute atleast part of a zoom lens system of the photographing lens 200.

The group of communication/control contacts 104 of the camera body 100consists of six contacts: a first contact 104 a (Fmin1/Inverse-SCKL), asecond contact 104 b (Fmin2/DATAL), a third contact 104 c (Fmin3/RESL),a fourth contact 104 d (CONTL), a fifth contact 104 e(Fmax1/Inverse-FBL) and a sixth contact 104 f (Fmax2/Inverse-FLB).Likewise, the group of communication/control contacts 204 of thephotographing lens 200 consists of six contacts: a first contact 204 a(Fmin1/Inverse-SCKL), a second contact 204 b (Fmin2/DATAL), a thirdcontact 204 c (Fmin3/RESL), a fourth contact 204 d (CONTL), a fifthcontact 204 e (Fmax1/Inverse-FBL) and a sixth contact 204 f(Fmax2/Inverse-FLB) which come into contact with the first through sixthcontacts 104 a through 104 f respectively, when the photographing lens200 is mounted to the camera body 100.

The power line from port P13 of the body CPU 111 to the fourth contact104 d constitutes a first body power line for supplying the first powerto the photographing lens 200. The power line from the battery 113 tothe power contact 105 (via the switch circuit 115) constitutes a secondbody power line for supplying the second power to the photographing lens200. The power line from the fourth contact 204 d to a port CONT of thelens ROM 221 constitutes a first lens power line for supplying powerfrom the camera body 100 to the photographing lens 200. The power linefrom the power contact 205 to a regulator 243 and to a switching circuit242 constitutes a second lens power line for supplying power from thecamera body 100 to the lens CPU 211. As shown in FIG. 1, the secondpower that is output from the camera body 100 to be input to thephotographing lens 200 via the power contacts 105 and 205 (VPZ) issupplied to the lens CPU 211 via the regulator 243 of the photographinglens 200 and also to the peripheral circuit 241 via a switching circuit242 of the photographing lens 200. The lens ROM 221 of the photographinglens 200 operates with constant voltage power (the first power) suppliedfrom the fourth contact 204 d (CONTL), whereas the lens CPU 211 operateswith the second power having a large power capacity supplied from thepower contact (VPZ) 205. The processing speed and the throughput of aCPU is generally proportional to the power consumption of the CPU.Accordingly, in the present embodiment of the SLR camera system to whichthe present invention is applied, providing the second power having alarge power capacity to the photographing lens 200 makes it possible forthe photographing lens 200 be provided therein with not only a CPU whichachieves a high throughput, but also high power components (i.e.,components which require a large current) such as a lens motor and animage-shake compensation device.

FIG. 3 is a block diagram of fundamental elements of acommunication/control system of the photographing lens 200. The firstcontact 204 a (Fmin1/Inverse-SCKL), the second contact 204 b(Fmin2/DATAL), the third contact 204 c (Fmin3/RESL), and the fourthcontact 204 d (CONTL) of the group of communication/control contacts204, of the photographing lens 200, are connected to four ports RES,SIO, Inverse-SCK, and CONT of the lens ROM 221, respectively.

The port RES of the lens ROM 221 serves as an input port via which thelens ROM 221 inputs a reset signal that changes the state of the lensROM 221 from a disabled state to an enabled state. The port SIO of thelens ROM 221 serves as an I/O port for serial communication. The portInverse-SCK of the lens ROM 221 serves as an input port via which thelens ROM 221 inputs a clock signal for communication from the camerabody 100. The port CONT of the lens ROM 221 serves an input port viawhich the lens ROM 221 inputs a constant voltage power (the first power)from the camera body 100.

The lens ROM 221 operates in accordance with the first power (constantvoltage power), which is supplied from the camera body 100 to be appliedto the port CONT of the lens ROM 221. The lens ROM 221 is set to changethe state of the lens ROM 221 from a disabled state to an enabled stateby a reset signal, which is input via the port RES of the lens ROM 221to enter the enabled state. Lens data written in the lens ROM 221 isread out therefrom to be output to the camera body 100 via the port SIOof the lens ROM 221, in synchronization with the clock signal input, viathe port Inverse-SCK. The port RES of the lens ROM 221 and the thirdcontact 204 c (Fmin3/RESL), which is connected to the port RES, alsoserve as a control line for changing the state of the lens ROM 221between an enabled state and a disabled state. Namely, the lens ROM 221operates while the first power is being supplied to the fourth contact204 d (CONTL), and the lens ROM 221 is set to change the state thereoffrom a disabled state to an enabled state if the level of the thirdcontact 204 c (Fmin3/RESL) falls to a low level, and the lens ROM 221 isset to change the state of the lens ROM 221 from an enabled state to adisabled state if the level of the third contact 204 c (Fmin3/RESL)rises to a high level. The timing chart thereof is shown in FIG. 20.

As shown in FIG. 3, the lens CPU 211 is provided with eight ports RXD,TXD, TXDEN, Inverse-SCK, P00, P01, INT and VCC, and the photographinglens 200 is provided with first through fourth high input voltage proofSchmitt inverters VCC1, VCC2, VCC3 and VCC4. The first contact 204 a(Fmin1/Inverse-SCKL) is connected to the port Inverse-SCK of the lensCPU 211 via the second and third Schmitt inverters VCC2 and VCC3, andthe second contact 204 b (Fmin2/DATAL) is connected to the port RXD ofthe lens CPU 211 and also to each of the two ports TXD and TXDEN of thelens CPU 211 via a first I/O protection circuit 212.

The port RXD of the lens CPU 211 serves as a data input port. The portTXD of the lens CPU 211 serves as a data output port. The port TXDEN ofthe lens CPU 211 serves as a control port via which the lens CPU 211determines whether data can be output from the port TXD of the lens CPU211. The port Inverse-SCK of the lens CPU 211 serves as an input portvia which the lens CPU 211 inputs a clock signal for communication fromthe camera body 100.

When the control port TXDEN of the lens CPU 211 is at a high level, ifthe level of a data output port TXD of the lens CPU 211 rises to a highlevel, a field effect transistor (FET) of the first I/O protectioncircuit 212 is turned OFF while a transistor of the first I/O protectioncircuit 212 is turned ON to thereby cause the level of port 212 a torise to a high level. On the other hand, if the level of the data outputport TXD of the lens CPU 211 falls to a low level when the control portTXDEN of the lens CPU 211 is at a high level, the field effecttransistor (FET) of the first I/O protection circuit 212 is turned ONwhile the transistor of the first I/O protection circuit 212 is turnedOFF to thereby cause the level of port 212 a to fall to a low level.Therefore, when the control port TXDEN of the lens CPU 211 is at a highlevel, the level of the data output port TXD of the lens CPU 211 isoutput from the first I/O protection circuit 212 via port 212 a to beinput to the second contact 204 b (Fmin2/DATAL).

Because each of the field effect transistor (FET) and the transistor ofthe first I/O protection circuit 212 is OFF when the control port TXDENis at a low level, port 212 a is in a high impedance state regardless ofthe level of the data output port TXD of the lens CPU 211.

The sixth contact 204 f (Fmax2/Inverse-FLB) is connected to each of thetwo ports P00 and P01 of the lens CPU 211 via a second I/O protectioncircuit 213, while the fifth contact 204 e (Fmax1/Inverse-FBL) isconnected to the port INT of the lens CPU 211 via the fourth high inputvoltage proof Schmitt inverter VCC4. The port P00 of the lens CPU 211serves as an output port while the port P01 of the lens CPU 211 servesas a control port via which the lens CPU 211 determines whether data canbe output from the port P00. The port INT of the lens CPU 211 serves asan input port via which the lens CPU 211 inputs an interrupt signal.

When the control port P01 of the lens CPU 211 is at a high level, if thelevel of the output port P00 of the lens CPU 211 rises to a high level,a field effect transistor (FET) of the second I/O protection circuit 213is turned OFF while a transistor of the second I/O protection circuit213 is turned ON to thereby cause the level of port 213 a to rise to ahigh level. On the other hand, if the level of the output port P00 ofthe lens CPU 211 falls to a low level when the control port P01 of thelens CPU 211 is at a high level, the field effect transistor (FET) ofthe second I/O protection circuit 213 is turned ON while the transistorof the second I/O protection circuit 213 is turned OFF to thereby causethe level of port 213 a to fall to a low level. Therefore, when theoutput port P00 of the lens CPU 211 is at a high level, the level of theoutput port P00 of the lens CPU 211 is output from the second I/Oprotection circuit 213 via port 213 a to be input to the sixth contact204 f (Fmax2/Inverse-FLB).

Because each of the field effect transistor (FET) and the transistor ofthe second I/O protection circuit 213 is OFF when the control port P01is at a low level, port 213 a is in a high impedance state regardless ofthe level of the output port P00 of the lens CPU 211.

The power contact 205 (VPZ) is connected to the power port VCC of thelens CPU 211 via a regulator 243. The lens CPU 211 operates withconstant voltage supplied from the regulator 243 to the power port VCC.

Selection between the communication channel for communication of thebody CPU 111 with the lens ROM 221 (i.e., lens ROMcommunication/old-type communication) and the communication channel forcommunication of the body CPU 111 with the lens CPU 211 (i.e., new-typecommunication) depends on a reset signal input to the third contact 204c (Fmin3/RESL). If the level of the input port RES of the lens ROM 221rises to a high level, the lens ROM 221 enters a disabled state and theSIO port of the lens ROM 221 enters a high impedance state. This makesthe aforementioned new-type lens communication between the body CPU 111and the lens CPU 211 possible.

The first contact 204 a (Fmin1/Inverse-SCKL), the second contact 204 b(Fmin2/DATAL), the third contact 204 c (Fmin3/RESL), the fifth contact204 e (Fmax1/Inverse-FBL) and the sixth contact 204 f(Fmax2/Inverse-FLB) maintain compatibility with conventional camerasystems using interchangeable lenses in which serial communicationbetween camera body and interchangeable lens is performed without usinga ROM (lens ROM) provided in an interchangeable lens. For instance, inorder to maintain compatibility with a camera body which can obtain theminimum f-number and the maximum f-number from the photographing lensmounted to the camera body, diodes for making the first, second, third,fifth and sixth contacts 204 a, 204 b, 204 c, 204 e and 204 f serve asaperture information contacts so that the camera body can input data onthe minimum f-number (the f-number at maximum aperture) via the first,second and third contacts 204 a, 204 b and 204 c and so that the camerabody can input data on the maximum f-number (the f-number at minimumaperture) via the fifth and sixth contacts 204 e and 204 f areselectively provided in a manner such that the camera body candistinguish between the maximum f-number and the minimum f-number bychecking continuity of each contact via the diodes.

FIG. 4 is a block diagram of fundamental components of a photographinglens 200 a which is provided with a lens CPU 211 a and a peripheralcircuit 241 a. The lens CPU 211 a operates with the first power suppliedfrom the fourth contact 204 d (CONTL), while the peripheral circuit 241a operates with power supplied from the power contacts 105 and 205(VPZ). In the photographing lens 200 a shown in FIG. 4, the powersupplied from the power contacts 105 and 205 (VPZ) is supplied to theperipheral circuit 241 a via the switching circuit 242.

FIG. 5 is a block diagram of fundamental components of a photographinglens 200 b which is provided with a lens CPU 211 b and a peripheralcircuit 241 b. The lens CPU 211 b operates with the first power suppliedfrom the fourth contact 204 d (CONTL). The photographing lens 200 bshown in FIG. 5 is not provided with either a power contact or aregulator corresponding to the power contact 205 (VPZ) or the regulator243, respectively. Each of the lens CPU 211 b and the peripheral circuit241 b operates with the first power supplied from the fourth contact 204d (CONTL).

In the photographing lens 200 a shown in FIG. 4, the camera body 100supplies the first power and the second power to the fourth contacts 104d and 204 d (CONTL) and the power contacts 105 and 205 (VPZ),respectively. On the other hand, in the photographing lens 200 b shownin FIG. 5, the camera body 100 supplies only the first power to thefourth contacts 104 d and 204 d (CONTL).

Fundamental operations of the camera body 100 and the photographing lens200 will be hereinafter discussed in detail with reference to the flowcharts shown in FIGS. 6 through 11 and the timing charts shown in FIGS.18 through 21B. FIG. 6 shows a flow chart for the main process of thecamera body 100 which is performed by the body CPU 111. Control entersthe main process immediately after the battery 113 is loaded into thecamera body 100. The camera body 100 performs both old-typecommunication (lens ROM communication) and new-type communicationbetween the camera body 100 and the photographing lens 200, whereas thecamera body 100 performs only the old-type communication (lens ROMcommunication) between the camera body 100 and the photographing lens200 if the photographing lens 200 is of any other type which is notprovided with any CPU corresponding to the lens CPU 211 of thephotographing lens 200 but provided with only a lens ROM, and whichaccordingly does not have any communication capability of thephotographing lens 200. It should be noted that operations or processeshaving step numbers bearing a prefix “CS” are related tocontrol/operation of the camera body 100 and that operations orprocesses having step numbers bearing a prefix “LS” are related tocontrol/operation of the photographing lens 200.

Fundamental commands for discussion of the present embodiment of the SLRcamera system are listed below. All the commands listed below are thosewhich are transmitted from the camera body 100 to the photographing lens200.

COMMANDS TRANSMITTED FROM CAMERA BODY TO LENS IN ORDER TO COMMAND LENSTO TRANSMIT DATA TO CAMERA BODY

70: Command for making the photographing lens send a lens status thereofto the camera body.

71: Command for making the photographing lens send a lens status thereofto the camera body and for making the lens CPU enter a sleep modetogether with the body CPU.

72: Command for making the photographing lens send information onfunctions that the photographing lens possesses, such as an image-shakecompensation function and a lens autofocus function, to the camera body.

7F: Command for a rear converter.

COMMANDS FOR DATA TRANSMISSION FROM CAMERA BODY TO LENS

B0: Command for sending data to the photographing lens.

B1: Command for sending data to the photographing lens and for makingthe lens CPU enter a sleep mode.

B2: Command for sending data on a driving-amount for the AF motorprovided in the photographing lens to the photographing lens.

INSTRUCTION COMMANDS TRANSMITTED FROM CAMERA BODY TO LENS

D0: Command for making the lens CPU enter the sleep mode.

D1: Command for turning OFF an image-shake compensation function.

D2: Command for turning ON the image-shake compensation function.

D3: Command for stopping the driving of the AF motor provided in thephotographing lens.

D4: Command for resuming the driving of the AF motor provided in thephotographing lens.

In the main process shown in FIG. 6, firstly it is determined whetherthe main switch SWMAIN is ON (step CS101). The operation at step CS101is repeated until the main switch SWMAIN is turned ON. If the mainswitch SWMAIN is turned ON (if YES at step CS101), a communicationidentification process (i.e., an old-type communication process at stepCS103 and a new-type communication setting request process at stepCS105) is performed. Command 72 is transmitted to the photographing lensto receive data therefrom (step CS107). Command 72 commands the lens CPU211 to output information on the functions that the photographing lenspossesses to the body CPU 111. The functions of the photographing lenscan include, e.g., an image-shake compensation function, a lensautofocus function and other functions which operate with power (thesecond power) supplied from the power contacts VPZ. In the presentembodiment of the SLR camera system, such information on functions thatthe photographing lens has is represented by 1-byte data (8-bit data),wherein the sixth bit represents the presence or absence of theautofocus function while the fourth bit represents the present orabsence of the image-shake compensation function. Upon receiving command72, the lens CPU 211 of the (new-type) photographing lens 200 outputsinformation on functions that the photographing lens 200 possesses tothe body CPU 111. FIG. 18 shows a timing chart for the aforementionedcommunication identification process from the moment the main switchSWMAIN is turned ON to the moment immediately after the commencement ofthe new-type communication process. FIGS. 19A and 19B each show a timingchart for a handshake operation performed between the camera body 100and the photographing lens 200 at the commencement of the communicationprocess. FIG. 20 shows a timing chart for the old-type communicationprocess. FIGS. 21A and 21B show timing charts for the new-typecommunication process.

After the operation at step CS107, the body CPU 111 sets a lens sleepflag SLP to “0” (step CS109). The lens sleep flag SLP “1” or “0”indicates that the lens CPU 211 is in the sleep mode (low poweroperation mode) or not in the sleep mode, respectively. The operationsor processes at steps CS103 through CS109 are performed when the mainswitch SWMAIN is turned from OFF to ON. Thereafter, the operations atand after step CS111 are repeated.

At step CS111, ON/OFF states of all the switch ports are input.Subsequently, a camera state information setting process is performed(step CS113). In the camera state information setting process, theinformation on the current states of some specific switches and a flashcharging system which is to be transmitted to the lens CPU 211 via thenew-type communication is prepared. Subsequently, the old-typecommunication process is performed (step CS115), and it is determinedwhether a photographing lens is mounted to the camera body 100 (stepCS117). If no photographing lens is mounted (if YES at step CS117), eachof the fourth contact 104 d (CONTL) and the power contact 105 (VPZ) isset to a low level (step CS119), and control returns to step CS101. Ifit is determined at step CS117 that a photographing lens is mounted (ifNO at step CS117), it is determined whether a new-type flag is “1”,i.e., whether the photographing lens currently mounted to the camerabody 100 is the (new-type) photographing lens 200 (step CS121). Thenew-type flag “1” indicates that the photographing lens currentlymounted to the camera body 100 is the (new-type) photographing lens 200.If the new-type flag is “1” (if YES at step CS121), it is determinedwhether a power hold flag PH is “0”, i.e., whether the camera body 100is not in a power hold state (step CS123). If the power hold flag PH is“0” (if YES at step CS123), it is determined whether the lens sleep flagSLP is “1” (step CS125). If the lens sleep flag SLP is “1” (if YES atstep CS125), control returns to step CS111 since the photographing lens200 is already in a sleep mode. If it is determined at step CS125 thelens sleep flag SLP is not “1”, command B1 is transmitted to the lensCPU 211 to make the photographing lens 200 enter the sleep mode (stepCS127). Subsequently, the lens sleep flag SLP is set to “1” (stepCS129), and control returns to step CS111.

If it is determined at step CS123 that the power hold flag PH is not “0”(if NO at step CS123), command B0 is transmitted to the lens CPU 211 tostart the lens CPU 211 (step CS131), and the lens sleep flag SLP is setto “0” (step CS133).

Subsequently, it is determined whether a rear converter 300 (see FIG.27) is mounted between the camera body and the photographing lens viathe result of the old-type communication process at step CS115 (stepCS134 a). If the rear converter 300 is mounted between the camera bodyand the photographing lens 200 (if YES at step CS134 a), command 7F,which commands the rear converter 300 to send information (data) thereonto the camera body, is transmitted to the camera body 100 (step CS134b), and control proceeds to step CS135. If no rear converter is mountedbetween the camera body and the photographing lens (if NO at step CS134a), control proceeds straight from step CS134 a to step CS135. At stepCS135 it is determined whether an image-shake compensating type lensflag is “1”, i.e., whether the photographing lens 200 mounted to thecamera body 100 is provided with an image-shake compensation device. Ifthe image-shake compensating type lens flag is “1” (if YES at stepCS135), an image-shake compensation data setting process, in whichpredetermined flags and data on image-shake compensation are set, isperformed (step CS137), and control proceeds to step CS139. If theimage-shake compensating type lens flag is not “1” (if NO at stepCS135), control skips step CS137 to proceed straight from step CS135 tostep CS139. If it is determined at step CS121 that the new-type flag isnot “1”, control proceeds straight from step CS121 to step CS139.

At step CS139 it is determined whether a SWMAIN flag is “0”, i.e.,whether the main switch SWMAIN has been turned from ON to OFF. If it isdetermined at step CS139 that the SWMAIN flag is not “1” (if NO at stepCS139), it is determined whether the photometering switch SWS is ON(step CS141). If the photometering switch SWS is not ON (if NO at stepCS141), control returns to step CS111. If the photometering switch SWSis ON (if YES at step CS141), control proceeds to step CS151. If it isdetermined at step CS139 that the SWMAIN flag is “1”, it is determinedwhether the new-type flag is “1” (step CS143). If it is determined atstep CS143 that the new-type flag is not “1”, control returns to stepCS101. If it is determined at step CS143 that the new-type flag is “1”(i.e., that the (new-type) photographing lens 200 is currently mountedto the camera body 100), it is determined at step CS145 whether a secondpower flag VpzONCPU is “1”, i.e., whether the photographing lens 200mounted to the camera body 100 is of a type which operates with powersupplied from the power contact 105 (VPZ). If it is determined at stepCS145 that the second power flag VpzONCPU is “1” (if YES at step CS145),the port VPZ is turned OFF, i.e., power supplied to the power contact105 (VPZ) is cut off (step CS147), and control returns to step CS101. Ifit is determined at step CS145 that the second power flag VpzONCPU isnot “1” (if NO at step CS145), control returns to step CS101 since thephotographing lens mounted to the camera body 100 does not operate withpower supplied from the power contact 105 (VPZ).

Operations which are performed after it is determined at step CS141 thatthe photometering switch SWS is ON will be hereinafter discussed withreference to the flow chart shown in FIG. 7.

If it is determined at step CS141 that the photometering switch SWS isON (if YES at step CS141), a photometering operation in whichphotometric data is input from a photometering sensor and an exposurearithmetic operation are performed in accordance with acurrently-selected photometering mode and a currently-selected exposuremode, respectively (step CS151). Subsequently, AF sensor data is inputfrom an AF sensor in accordance with a currently-selected AF mode, whilea predetermined AF arithmetic operation necessary for attaining anin-focus state is performed in accordance with the input AF sensor data(step CS153).

Subsequently, it is determined whether the new-type flag is “1” (stepCS155). If the new-type flag is “1” (if YES at step CS155), it isdetermined whether a lens AF flag is “1”, i.e., whether thephotographing lens 200 mounted to the camera body 100 has a lensautofocus function (step CS157). If the lens AF flag is “1” (if YES atstep CS157), it is determined whether an AFON flag is “1” (step CS159).The AFON flag “1” indicates that the AF function is ON, i.e., the AFfunction is in operation. If the AFON flag is “1” (if YES at stepCS159), data on a driving-amount of an AF lens (focusing lens group) ofthe photographing lens is transmitted to the lens CPU 211 (step CS161),and subsequently control proceeds to step CS163. If at least one of thenew-type flag, the lens AF flag and the AFON flag is not “1”, controlskips the operation at step CS161 and proceeds to step CS163.

At step CS163 it is determined whether an in-focus state has beenobtained. If an in-focus state has not been obtained (if NO at stepCS163), control returns to step CS111 shown in FIG. 6. Accordingly, inthe present embodiment of the SLR camera system, an in-focus prioritycontrol in which the shutter cannot be released unless an in-focus stateis obtained is adopted. A release priority control in which the shuttercan be released even in an out-of-focus state can be adopted. In thiscase, the operation at step CS163 is omitted.

If it is determined at step CS163 that an in-focus state has beenobtained (if YES at step CS165), it is determined whether the releaseswitch SWR is ON (step CS165). If the release switch SWR is OFF (if NOat step CS165), control returns to step CS111.

If the release switch SWR is ON (if YES at step CS165), it is determinedwhether the new-type flag is 1 (step CS167). If the new-type flag is 1(if YES at step CS167), a release stage indicator RLS is set to “1”, andinformation on the indicator RLS “1” is transmitted to the lens CPU 211(step CS169). Subsequently control proceeds to step CS171. If thenew-type flag is not 1 (if NO at step CS167), control skips step CS169to proceed straight from step CS167 to step CS171, so that theinformation on the indicator RLS “1” is not transmitted to the lens CPU211. The release stage indicator RLS “1” informs the photographing lens200 of a stage at which the quick return mirror is moving toward theretracted position thereof after the release switch SWR has been turnedON.

At step CS171 the mirror circuit 123 is actuated to drive a mirror drivemotor so that the quick return mirror of the camera body 100 moves up toa retracted position. Subsequently, it is determined whether thenew-type flag is 1 (step CS173). If the new-type flag is 1 (if YES atstep CS173), the release stage indicator RLS is set to “2”, andinformation on the stage indicator RLS “2” is transmitted to the lensCPU 211 (step CS175). Subsequently, control proceeds to step CS177. Ifthe new-type flag is not 1 (if NO at step CS173), control skips stepCS175 to proceed straight from step CS173 to step CS177, so that theinformation on the indicator RLS “2” is not transmitted to the lens CPU211. The release stage indicator RLS “2” informs the photographing lens200 of a stage at which a film frame is under exposure after the quickreturn mirror has moved up to the retracted position thereof.

At step CS177 the shutter circuit 125 is actuated to drive the focalplane shutter mechanism to perform an exposure operation. Uponcompletion of the exposure operation, it is determined whether thenew-type flag is 1 (step CS179). If the new-type flag is 1 (if YES atstep CS179), the release stage indicator RLS is set to “3”, andinformation on this indicator RLS “3” is transmitted to the lens CPU 211(step CS181). Subsequently control proceeds to step CS183. If thenew-type flag is not 1 (if NO at step CS179), control skips step CS181to proceed straight from step CS179 to step CS183, so that theinformation on the indicator RLS “3” is not transmitted to the lens CPU211. The release stage indicator RLS “3” informs the photographing lens200 of a stage at which film is wound after the exposure operation hasbeen completed.

At step CS183 a film-winding operation in which the film-winding circuit127 is actuated to drive a film motor (shutter charge motor) to windfilm by one frame is performed while a shutter charge operation isperformed (step CS183). Subsequently, it is determined whether thenew-type flag is “1” (step CS185). If the new-type flag is 1 (if YES atstep CS185), the release stage indicator RLS is set to “0”, andinformation on this indicator RLS “0” is transmitted to the lens CPU 211(step CS187). Subsequently control returns to step CS111. If thenew-type flag is not 1 (if NO at step CS185), control skips step CS187to return straight from step CS185 to step CS111, so that theinformation on the indicator RLS “0” is not transmitted to the lens CPU211. The release stage indicator RLS “0” informs the photographing lensof a stage at which the aforementioned film-winding operation has beencompleted, i.e., a state at which the shutter can be released.

In the above described release process at and after step CS151, therelease stage indicator RLS that indicates a stage in the releaseprocess is transmitted to the lens CPU 211 each time each stage in therelease process is completed, if the (new-type) photographing lens 200is mounted to the camera body 100. This makes it possible for thephotographing lens 200 to perform operations which correspond tooperational state and stage of the camera body 100.

The communication identification process, which is composed of theold-type communication process at step CS103 and the new-typecommunication setting request process at step CS105, will be hereinafterdiscussed in detail with reference to the flow charts shown in FIGS. 8Aand 8B. FIG. 8A shows operations of the communication identificationprocess, while FIG. 8B shows operations of the photographing lens 200which are performed by the lens CPU 211 in accordance with operations ofthe new-type communication setting request process at step CS105. Thenew-type communication setting request process at step CS105 includesoperations at steps CS203 through CS215 shown in FIG. 8A.

Control enters the communication identification process immediatelyafter the power of the camera body 100 is turned ON. The communicationidentification process is performed to identify the type ofphotographing lens 200 and communication protocols used therefor.Immediately after the power of the camera body 100 is turned ON (i.e.,immediately after it is determined that the main switch SWMAIN is ON atstep CS101), control enters the old-type communication process at stepCS103. In the old-type communication process at step CS103, it isdetermined whether the photographing lens currently mounted to thecamera body 100 is provided with a lens ROM from which the body CPU 111can read out any predetermined lens data, and subsequently the old-typecommunication (lens ROM communication) is performed in accordance withcommunication protocols used for the photographing lens having such alens ROM, if it is determined that the photographing lens currentlymounted to the camera body 100 is provided with such a lens ROM. In thelens ROM communication, predetermined lens data written in the lens ROM221 are read therefrom. This lens data includes data on the lens type ofthe currently mounted photographing lens.

Upon completion of the lens ROM communication, it is determined, fromthe result of the lens ROM communication, whether the photographing lens200 currently mounted to the camera body 100 is a new type ofphotographing lens (step CS203). If it is determined that a new type ofphotographing lens is not mounted to the camera body 100 (if NO at stepCS203), control exits the communication identification process, and fromthis time on only the old-type communication (lens ROM communication) isperformed between the photographing lens 200 and the camera body 100.

If it is determined at step CS203 that the photographing lens 200mounted to the camera body 100 is a new type of photographing lens (ifYES at step CS203), it is determined whether the currently-mounted(new-type) photographing lens 200 is of a type (VpzON type) whichoperates with power supplied from the power contact 105 (VPZ) (stepCS205). If the currently-mounted photographing lens 200 is a VpzON typelens (if YES at step CS205), the power contact 105 (VPZ) is turned ON;namely, power is supplied to the power contact 105 (VPZ) (step CS207).Subsequently, control proceeds to step CS209. On the other hand, if thecurrently-mounted photographing lens 200 is not a VpzON type lens (if NOat step CS205), control skips step CS207 to proceed straight from stepCS205 to step CS209, so that no power is supplied to the power contact105 (VPZ).

At step CS209 the level of the fifth contact 104 e (Fmax1/Inverse-FBL)is made to fall to a low level (“Lo” or “L” level), and subsequently itis determined whether the level of the sixth contact 104 f(Fmax2/Inverse-FLB) is a low level (step CS211). The operation at stepCS211 is repeated as long as the level of the sixth contact 104 f(Fmax2/Inverse-FLB) is a high level. If it is determined at step CS211that the level of the sixth contact 104 f (Fmax2/Inverse-FLB) is a lowlevel (if YES at step CS211), the level of the fifth contact 104 e(Fmax1/Inverse-FBL) is raised to a high level (“Hi” or “H” level) (stepCS213), and subsequently it is determined whether the level of the sixthcontact 104 f (Fmax2/Inverse-FLB) is a high level (step CS215). Theoperation at step CS215 is repeated as long as the level of the sixthcontact 104 f (Fmax2/Inverse-FLB) is a low level. If it is determined atstep CS215 that the level of the sixth contact 104 f (Fmax2/Inverse-FLB)is a high level (if YES at step CS215), this means that the (new typeof) photographing lens 200 mounted to the camera body 100 operatesnormally, so that control comes out of the communication identificationprocess, and from this time on new-type communication is performedbetween the photographing lens 200 (the lens CPU 211) and the camerabody 100 (the body CPU 111).

On the other hand, while the camera body 100 performs the operations atsteps CS207 through CS215, the (new-type) photographing lens 200performs the operations represented by the flow chart shown in FIG. 8B.If the power contact 105 (VPZ) is supplied with power at step CS207,this power is supplied to the photographing lens 200 via the powercontact 205 (VPZ). This causes the regulator 243 to supply a constantvoltage to the lens CPU 211, which in turn causes the lens CPU 211 toinitialize internal RAM thereof (step LS201). Subsequently, it isdetermined whether the level of the fifth contact 204 e(Fmax1/Inverse-FBL) is a low level (step LS203). The operation at stepLS203 is repeated as long as the level of the fifth contact 204 e(Fmax1/Inverse-FBL) is a high level. If it is determined, via the fifthcontact 204 e (Fmax1/Inverse-FBL) and the port INT of the lens CPU 211,that the level of the fifth contact 104 e (Fmax1/Inverse-FBL) falls to alow level due to the operation at step CS209 (if YES at step LS203), thelevel of the sixth contact 204 f (Fmax2/Inverse-FLB) is made to fall toa low level via the port P00 of the lens CPU 211 (step LS205).Thereafter, it is determined whether the level of the fifth contact 204e (Fmax1/Inverse-FBL) is a high level (step LS207). The operation atstep LS207 is repeated as long as the level of the fifth contact 204 e(Fmax1/Inverse-FBL) is a low level. If it is determined that the levelof the fifth contact 104 e (Fmax1/Inverse-FBL) rises to a high level dueto the operation at step CS213 (if YES at step LS207), the level of thesixth contact 204 f (Fmax2/Inverse-FLB) is raised to a high level (stepLS209). Subsequently, control comes out of the communicationidentification process, and from this time on the new-type communicationis performed between the (new-type) photographing lens 200 (the lens CPU211) and the camera body 100 (the body CPU 111).

FIG. 18 shows a timing chart for the communication identificationprocess that is performed between the body CPU 111 of the camera body100 and the lens CPU 211 of the photographing lens 200. In thecommunication identification process, the fifth contacts 104 e and 204 e(Fmax1/Inverse-FBL) and the sixth contacts 104 f and 204 f(Fmax2/Inverse-FLB) are used to serve as handshake connectors/lines (seeFIGS. 19A and 19B). Immediately after the power of the camera body 100is turned ON, the body CPU 111 makes the level of the fourth contact 204d (CONTL) rise to a high level to perform the old-type communication(lens ROM communication).

OLD-TYPE COMMUNICATION (LENS ROM COMMUNICATION)

FIG. 20 shows a timing chart for the old-type communication processbetween the camera body 100 and the photographing lens 200, i.e.,between the body CPU 111 and the lens ROM 221. In the lens ROMcommunication, predetermined lens data written in the lens ROM 221 areread therefrom. The levels of the first contact 104 a(Fmin1/Inverse-SCKL), the third contact 104 c (Fmin3/RESL) and thefourth contact 104 d (CONTL) of the group of communication/controlcontacts 104 of the camera body 100 before the commencement of the lensROM communication are a high level, a high level and a low level,respectively. The second contact 104 b (Fmin2/DATAL) before thecommencement of the lens ROM communication is in a high impedance(floating) state.

The body CPU 111 makes the level of the fourth contact 104 d (CONTL)rise to a high level to actuate the lens ROM 221 when starting the lensROM communication. Subsequently, after waiting a predetermined period oftime necessary for the lens ROM to operate with stability, the body CPU111 makes the level of the third contact 104 c (Fmin3/RESL) fall to alow level to change a state of the lens ROM 221 from a disabled state toan enabled state. Thereafter, if the body CPU 111 outputs a clock signalfrom the first contact 104 a (Fmin1/Inverse-SCKL), the lens ROM 221reads out predetermined data from an internal ROM thereof to output thepredetermined data to the second contact 204 b (Fmin2/DATAL), so thatthe body CPU 111 inputs the predetermined data via the second contact104 b (Fmin2/DATAL). The body CPU 111 makes the level of the thirdcontact 104 c (Fmin3/RESL) rise to a high level upon having input apredetermined number of bytes of lens data. In the present embodiment ofthe SLR camera system, the last one or few bytes of the lens data arespare bytes. These spare bytes can receive data (rear converter data)output from a ROM (memory/rear converter memory) 321 provided in therear converter 300 when the rear converter 300 is mounted between thecamera body and the photographing lens. More specifically, when the lensROM communication (the old-type communication) is performed with therear converter 300 being mounted between the camera body 100 and thephotographing lens 200, as shown in FIG. 27, a predetermined number ofbytes serving as the aforementioned spare bytes of the lens data storedin the lens ROM 221 are in a floating state with dummy data so that thespare bytes are transmitted to the camera body 100 with the data outputfrom the ROM 321 of the rear converter 300 being added to the sparebytes. The body CPU 111 can determine whether the rear converter 300 isconnected between the camera body 100 and the photographing lens 200 inaccordance with the input data of the spare bytes.

Information on the lens type is included in data obtained via the abovedescribed lens ROM communication, and includes data (new-type lensbit=“1”) for identification of the new-type photographing lens (i.e., alens which can perform the new-type communication) and data (VpzONCPUbit=“1”) for identification of the necessity for power supply. The bodyCPU 111 of the camera body 100 identifies whether or not thephotographing lens 200 mounted to the camera body 100 is a new type ofphotographing lens from such data.

NEW-TYPE COMMUNICATION

Upon completion of the old-type communication, the body CPU 111 startssupplying power to the power contacts 105 and 205 (VPZ). Subsequently,the body CPU 111 makes the level of the fifth contact 104 e (204 e)(Fmax1/Inverse-FBL) fall to a low level to interrupt the lens CPU 211,and waits for the level of the sixth contact 104 f (204 f)(Fmax2/Inverse-FLB) to fall to a low level, i.e., waits for the lens CPU211 to make the level of the sixth contact 204 f (Fmax2/Inverse-FLB)fall to a low level. The fifth contact 104 e (204 e)(Fmax1/Inverse-FBL), the sixth contact 104 f (204 f)(Fmax2/Inverse-FLB), and the second contact 104 b (204 b) (Fmin2/DATAL)correspond to a first communication/control contact, a secondcommunication/control contact and an data I/O contact, respectively.

Upon the interrupt by the body CPU 111, the lens CPU 211 “wakes up” andoperates normally if in the sleep mode, and initializes the internal RAMthereof. Subsequently, upon completion of the initializing operation,the lens CPU 211 makes the level of the sixth contact 204 f(Fmax2/Inverse-FLB) fall to a low level, and waits for the level of thefifth contact 204 e (104 e) (Fmax1/Inverse-FBL) to rise to a high level.

Immediately after the level of the sixth contact 104 f (204 f)(Fmax2/Inverse-FLB) falls to a low level, the body CPU 111 makes thelevel of the fifth contact 104 e (204 e) (Fmax1/Inverse-FBL) rise to ahigh level, and waits for the level of the sixth contact 104 f (204 f)(Fmax2/Inverse-FLB) to rise to a high level.

Immediately after the level of the fifth contact 204 e (104 e)(Fmax1/Inverse-FBL) rises to a high level, the lens CPU 211 makes thesixth contact 204 f (104 f) (Fmax2/Inverse-FLB) rise to a high level tocomplete the communication identification process.

Upon identifying that the level of the sixth contact 104 f (204 f)(Fmax2/Inverse-FLB) has risen to a high level, the body CPU 111completes the communication identification process.

From this time on, data and commands are transmitted between the camerabody 100 and the photographing lens 200 via the new-type communication.

The camera state information setting process performed at step CS113will be hereinafter discussed in detail with reference to the flow chartshown in FIG. 10. In the camera state information setting process, theinformation on the current states of specific switches and a flashcharging system which is to be transmitted to the lens CPU 211 via thenew-type communication is prepared. Specifically, in the presentembodiment of the SLR camera system, it is determined whether theautofocus system of the camera body 100 is in operation, whether anelectronic flash (strobe) is in the middle of charging, whether a powerhold timer has expired since the photometering switch SWS is turned OFF,and whether the main switch SWMAIN is ON, wherein flags which indicatethese states are set as state information.

In the camera state information setting process, it is determinedwhether the photometering switch SWS is ON (step CS301). If thephotometering switch SWS is ON (if YES at CS301), it is determinedwhether the AF switch SWAF is ON, i.e., whether the autofocus mode hasbeen set via the AF switch SWAF (step CS303). If the AF switch SWAF isON (if YES at step CS303), the AFON flag is set to “1” (step CS305) andsubsequently control proceeds to step CS309. If the AF switch SWAF isnot ON (if NO at step CS303), the AFON flag is set to “0” (step CS307),and subsequently control proceeds to step CS309. If the AF switch SWAFis not ON (if NO at step CS301), the AFON flag is set to “0” (stepCS307), and subsequently control proceeds to step CS309.

At step CS309 it is determined whether the electronic flash is in themiddle of charging. If the electronic flash is in the middle of charging(if YES at step CS309), a flag PAUSE is set to “1” (step CS311), andsubsequently control proceeds to step CS315. The flag PAUSE is set to“1” when any high power operation which requires a large current isperformed at present. The electric flash charging operation correspondsto a high power operation in the present embodiment of the SLR camerasystem. Therefore, the flag PAUSE is set to “1” when the electronicflash is in the middle of charging. When the flag PAUSE is “1”, thephotographing lens 200 suspends all high power operations thereof. Thefilm-winding operation and the shutter charge operation are also highpower operations performed in the present embodiment of the SLR camerasystem.

At step CS315 it is determined whether the photometering switch SWS isON. If the photometering switch SWS is ON (if YES at CS315), the powerhold flag PH is set to “1” (step CS321), and subsequently controlproceeds to step CS323. If the photometering switch SWS is not ON (if NOat CS315), it is determined whether the power hold timer has expired(step CS317). If the power hold timer has expired (if YES at stepCS317), the power hold flag PH is set to “0” (step CS319), andsubsequently control proceeds to step CS323. If the power hold timer hasnot expired (if NO at step CS317), the power hold flag PH is set to “1”(step CS321), and subsequently control proceeds to step CS323. The powerhold timer measures the time from the moment the photometering switchSWS is turned OFF to the moment the body CPU 111 enters a sleep mode,and the power hold flag PH “1” or “0” indicates that the camera body 100is in operation or in a sleep mode (a power saving mode), respectively.

At step CS323, it is determined whether the main switch SWMAIN is ON. Ifthe main switch SWMAIN is ON (if YES at step CS323), the SWMAIN flag isset to “1” (step CS325), and subsequently control returns. If the mainswitch SWMAIN is not ON (if NO at step CS323), the SWMAIN flag is set to“0” (step CS327), and subsequently control returns.

NEW-TYPE COMMUNICATION (LENS CPU COMMUNICATION)

Timing charts in the new-type communication between the lens CPU 211 andthe body CPU 111 are shown in FIGS. 18, 19A, 19B, 21A and 21B. In thenew-type communication, the fifth contacts 104 e and 204 e(Fmax1/Inverse-FBL), and the sixth contacts 104 f and 204 f(Fmax2/Inverse-FLB), are used to serve as handshake connectors/lines(see FIGS. 19A and 19B). The level of each of the fifth contact 104 e(Fmax1/Inverse-FBL) and the sixth contact 104 f (Fmax2/Inverse-FLB) ispulled up by the body CPU 111 so that the fifth contact 104 e(Fmax1/Inverse-FBL) and the sixth contact 104 f (Fmax2/Inverse-FLB)cannot short circuit when the new type of photographing lens 200 ismounted to or dismounted from the camera body 100 (see FIGS. 19A and19B).

NEW-TYPE COMMUNICATION SETTING REQUEST PROCESS

The new-type communication setting request process performed at stepCS105 will be hereinafter discussed in detail with reference to the flowchart shown in FIG. 9.

In the new-type communication setting request process, firstly it isdetermined whether the new-type flag is “1”, i.e., whether thephotographing lens 200 currently mounted to the camera body 100 is a newtype of photographing lens (step CS221). If the new-type flag is not “1”(if NO at step CS221), control returns since the currently mountedphotographing lens 200 is not a new type of photographing lens. If thenew-type flag is “1” (if YES at step CS221), operations at and aftersteps CS223 in the new-type communication setting request process areperformed since the photographing lens 200 currently mounted to thecamera body 100 is a new type of photographing lens 200 which allowsnew-type communication.

At step CS223 it is determined whether the second power flag VpzONCPU is“1”. If the second power flag VpzONCPU is “1” (if YES at step CS223),the power contact 105 (VPZ) is turned ON, namely, power is supplied tothe power contact 105 (VPZ) (step CS225). Subsequently, control proceedsto step CS227. On the other hand, if the second power flag VpzONCPU isnot “1” (if NO at step CS223), control skips step CS225 to proceedstraight from step CS221 to step CS225, so that no power is supplied tothe power contact 105 (VPZ).

At step CS227, the level of the fifth contact 104 e (Fmax1/Inverse-FBL)is made to fall to a low level, and subsequently it is determinedwhether the level of the sixth contact 104 f (Fmax2/Inverse-FLB) is alow level (step CS229). The operation at step CS229 is repeated as longas the level of the sixth contact 104 f (Fmax2/Inverse-FLB) is a highlevel. If it is determined at step CS229 that the level of the sixthcontact 104 f (Fmax2/Inverse-FLB) is a low level (if YES at step CS229),the level of the fifth contact 104 e (Fmax1/Inverse-FBL) is raised to ahigh level (step CS231), and subsequently it is determined whether thelevel of the sixth contact 104 f (Fmax2/Inverse-FLB) is a high level(step CS233). The operation at step CS233 is repeated as long as thelevel of the sixth contact 104 f (Fmax2/Inverse-FLB) is a low level. Ifit is determined at step CS233 that the level of the sixth contact 104 f(Fmax2/Inverse-FLB) is a high level (if YES at step CS233), controlreturns, i.e., control proceeds to step CS107.

IMAGE-SHAKE COMPENSATION DATA SETTING PROCESS

The image-shake compensation data setting process, which is performed atstep CS137 on condition that the photographing lens 200 mounted to thecamera body 100 is of a type which incorporates an image-shakecompensation device, will be hereinafter discussed in detail withreference to the flow chart shown in FIG. 11. FIG. 12A shows fundamentalelements of a control system of an embodiment (first embodiment) of thephotographing lens 200 which incorporates an image-shake compensationdevice. FIG. 12B shows a conceptual diagram of a compensation lens (animage-stabilizing optical system) LC of the image-shake compensationdevice. The image-shake compensation device includes a pair of sensors,i.e., an X-direction angular speed sensor (horizontal-vibration sensor)251 and a Y-direction angular speed sensor (vertical-vibration sensor)252, for determining magnitude and direction of the vibration of thephotographing lens 200 due to hand movement. If a state where thephotographing lens 200 is properly mounted to the camera body 100 andnormally held in a horizontal position is considered as a referencestate, the X-direction angular speed sensor 251 senses the angular speedof the photographing lens 200 in the horizontal direction of the opticalaxis thereof (in the X-direction about the Y-axis), while theY-direction angular speed sensor senses the angular speed of thephotographing lens 200 in the horizontal direction of the optical axisthereof (in the Y-direction about the X-axis) wherein an intersectionpoint of the optical axis of the photographing lens 200 and the pictureplane defines the intersection point of the X-axis and the Y-axis. Eachof the vertical and horizontal vibration sensors can be a conventionalgyro sensor. The vertical-vibration sensor exclusively senses the shakeof the photographing lens 200 in the vertical direction, while thehorizontal-vibration sensor exclusively senses the shake of thephotographing lens 200 in the horizontal direction.

The image-shake compensation device of the photographing lens 200 isprovided with the compensation lens LC (see FIG. 12B), and operates tocompensate the shaking of the object image on the picture plane bydriving the compensation lens LC in the X-direction and the Y-directionwith an X-motor 254 and a Y-motor 257, respectively, in a planeperpendicular to the optical axis of the photographing lens 200. Theposition of the compensation lens LC is sensed by the number of pulsesoutput from each of an X-direction photo-interrupter 255 and aY-direction photo-interrupter 258 when the compensation lens LC isdriven, wherein a position where the optical axis of the compensationlens LC coincides with the optical axis of the photographing lens 200 isregarded as a reference position. Rotation of each of the X-motor 254and the Y-motor 257 is controlled by the lens CPU 211 via an X-motordriver 253 and a Y-motor driver 256, respectively.

Note that the X-direction angular speed sensor 251, the Y-directionangular speed sensor 252, the X-motor driver 253, the Y-motor driver256, the X-motor 254, the Y-motor 257, X-direction photo-interrupter255, the Y-direction photo-interrupter 258, and the compensation lens LCcollectively constitute the image-shake compensation device.

The lens CPU 211 serves as a controller and an arithmetic processingunit for the image-shake compensation device. The lens CPU 211 startsoperating immediately after the image-shake compensation switch SW1 isturned ON to determine the direction of driving of the compensation lensLC and the amount of movement (speed) thereof to drive the X-motor 254and the Y-motor 257.

In the image-shake compensation data setting process shown in FIG. 11,firstly, it is determined whether the main switch flag SWMAIN haschanged from “0” to “1” (step CS401). If the main switch flag SWMAIN haschanged from “0” to “1” (if YES at step CS401), command 70 istransmitted to the photographing lens 200 to receive data therefrom(step CS403). Subsequently, the lens CPU 211 waits for an initializeflag Init “0” to be transmitted from the camera body 100 (step CS405).Namely, it is determined at step CS405 whether the initialize flag Initis “0”.

Command 70 is data which is transmitted from the camera body 100 to thephotographing lens 200 to make the photographing lens 200 send thestatus thereof (status data) to the camera body 100. In the presentembodiment of the SLR camera system, the status data which istransmitted from the photographing lens 200 to the camera body 100,immediately after the photographing lens 200 receives command 70, isrepresented by one-byte data, wherein the 7th bit thereof is defined asthe initialize flag Init. The 0th bit of the one-byte data is defined asan identification bit which indicates whether an AF switch is ON or OFF.The 1st bit of the one-byte data is defined as an identification bitwhich indicates whether the diaphragm is set automatically or manually.The 6th bit of the one-byte data is defined as an identification bitwhich indicates whether any function of the photographing lens 200 is inoperation or not. Each of the second through fifth bits is undefined.Therefore, each of the second through fifth bits can be defined as aspecific identification bit if any new function is added to thephotographing lens 200. It should be noted that 0 bit or no dataindicates negation.

The initialize flag Init is changed from “1” to “0” and output from thephotographing lens 200 to the camera body 100 when an operation at stepLS117 or LS125, in which the compensation lens LC is driven to return tothe initial position thereof where the optical axis of the compensationlens coincides with the optical axis of the photographing lens 200, iscompleted. If it is determined at step CS405 that the initialize flagInit is “0”, control proceeds to step CS407. If it is determined at stepCS401 that the main switch flag SWMAIN has not changed from “0” to “1”(if NO at step CS401), control proceeds straight from step CS401 toCS407.

At step CS407, it is determined whether the main switch flag SWMAIN haschanged from “1” to “0”. If the main switch flag SWMAIN has changed from“1” to “0” (if YES at step CS407), this means that the main switchSWMAIN has turned from ON to OFF, so that subsequently command 70 istransmitted to the photographing lens 200 to receive data therefrom(step CS409). Subsequently, the lens CPU 211 waits for the initializeflag Init “0” to be transmitted from the camera body 100 (step CS411).Namely, it is determined at step CS411 whether the initialize flag Initis “0”. Control returns to step CS409 if the initialize flag Init is not“0”.

If it is determined at step CS411 that the initialize flag Init is “0”,control proceeds to step CS413. If it is determined at step CS407 thatthe main switch flag SWMAIN has not changed from “1” to “0” (if NO atstep CS407), control proceeds straight from step CS407 to CS413.

If it is determined at step CS413 that the power hold flag PH haschanged from “1” to “0” (if YES at step CS413), command 70 istransmitted to the photographing lens 200 to receive data therefrom(step CS415). Subsequently, the lens CPU 211 waits for the initializeflag Init “0” to be transmitted from the camera body 100 (step CS417).Namely, it is determined at step CS417 whether the initialize flag Initis “0”. Control returns to step CS415 if the initialize flag Init is not“0”. If it is determined at step CS417 that the initialize flag Init is“0”, control proceeds to step CS419. If it is determined at step CS413that the power hold flag PH has not changed from “1” to “0” (if NO atstep CS413), control proceeds straight from step CS413 to CS419.

At step CS419 it is determined whether the image-shake compensationswitch SW1 has been turned from ON to OFF. If the image-shakecompensation switch SW1 has been turned from ON to OFF (if YES at stepCS419), command D1 (individual function data) for turning OFF theimage-shake compensation function of the photographing lens 200 istransmitted thereto (step CS421), and subsequently control proceeds tostep CS423. Upon receiving command D1, the photographing lens 200completes the image-shake compensation operation. If the image-shakecompensation switch SW1 has not been turned from ON to OFF (if NO atstep CS419), control skips CS421 to proceed straight from step CS419 tostep CS423. At step CS423 it is determined whether the image-shakecompensation switch SW1 has been turned from OFF to ON. If theimage-shake compensation switch SW1 has been turned from OFF to ON (ifYES at step CS423), command D2 (individual function data) for turning ONthe image-shake compensation function of the photographing lens 200 istransmitted thereto (step CS425), and subsequently control returns. Ifthe image-shake compensation switch SW1 has not been turned from OFF toON (if NO at step CS423), control skips CS425 and returns. Uponreceiving command D2, the photographing lens 200 starts the image-shakecompensation operation.

Fundamental operations and processes performed by the lens CPU 211 ofthe photographing lens 200 that incorporates the image-shakecompensation device will be hereinafter discussed in detail withreference to the flow charts shown in FIGS. 13 through 17. FIG. 13 showsa flow chart for the main process of the photographing lens 200 which isperformed by the lens CPU 211. Control enters the main processimmediately after the lens CPU 211 is supplied with power via theoperation at step CS225, at which power is supplied to the power contact105 (VPZ).

In the main process shown in FIG. 13, firstly the lens CPU 211initializes internal RAM and ports thereof (step LS101). Subsequently, anew-type communication setting process (“new-type communication settingprocess” shown in FIG. 14) is performed (step LS103). In this process, a1 ms-timer interrupt (see FIG. 15) and an interrupt via the port(inverse) INT of the lens CPU 211 (see FIG. 16) are enabled to receivean interrupt from the camera body 100 to thereby make the new-typecommunication possible between the new type of photographing lens(photographing lens 200) and the camera body 100.

Subsequently, it is determined whether a sleep flag which is set to “1”at step LS433 or LS 437 is “1” (step LS105). If the sleep flag is “1”(if YES at step LS105), the lens CPU 211 stops operations of internaldevices of the photographing lens 200 such as the lens motor (stepLS107), the sleep flag is set to “0” (step LS109), and the lens CPU 211enters the sleep mode (step LS111). The lens CPU 211 “wakes up” uponreceiving an interrupt signal via the port (inverse) INT thereof.

If it is determined at step CS105 that the sleep flag is not “1” (if NOat step LS105), it is determined whether a compensation lens reset flagis “1” (step LS113). If the compensation lens reset flag is “1” (if YESat step LS113), the initialize flag Init is set to “1” (step LS115).Subsequently, a resetting operation is performed (step LS117). In theresetting operation, the X-motor 254 and Y-motor 257 are driven to movethe compensation lens LC to firstly a predetermined mechanical extremity(reference point) in the range of movement of the compensation lens LC,and subsequently the initial position (central position) thereof wherethe optical axis of the compensation lens LC coincides with the opticalaxis of the photographing lens 200. After the resetting operation isperformed, the compensation lens reset flag and the initialize flag areset to “0” (step LS119), and control proceeds to step LS121. Accordingto this resetting operation, the absolute position of the compensationlens LC is secured, and accordingly the compensation lens LC can bepositioned precisely at the initial position (central position) thereof.

If it is determined at step LS113 that the compensation lens reset flagis not “1”, it is determined whether a compensation lens center flag is“1” (step LS121). If the compensation lens center flag is not “1” (if NOat step LS121), control returns to step LS105. If the compensation lenscenter flag is “1” (if YES at step LS121), the initialize flag Init isset to “1” (step LS123). Subsequently, a centering operation isperformed in which the X-motor 254 and Y-motor 257 are driven to movethe compensation lens LC to the initial position (central position)where the optical axis of the compensation lens LC coincides with theoptical axis of the photographing lens 200 (step LS125). Subsequently,the compensation lens center flag and the initialize flag are set to “0”(step LS127), and control returns to step LS105.

The new-type communication setting process performed at step LS103 willbe hereinafter discussed in detail with reference to the flow chartshown in FIG. 14. In the new-type communication setting process, firstlyit is determined whether the level of the fifth contact 204 e(Fmax1/Inverse-FBL) is a low level (step LS221). If the level of thefifth contact 204 e (Fmax1/Inverse-FBL) is not a low level (if NO stepLS221), the operation at step LS221 is performed again, so that theoperation at step LS221 is repeated until the level of the fifth contact204 e (Fmax1/Inverse-FBL) falls to a low level. If the level of thefifth contact 204 e (Fmax1/Inverse-FBL) is a low level (if YES stepLS221), the sixth contact 204 f (Fmax2/Inverse-FLB) is made to fall to alow level (step LS223), and subsequently a communication setting processis performed (step LS225). The communication setting process includes asetting process for serial communication, and an interrupt enablingprocess via the port (inverse) INT of the lens CPU 211.

Upon completion of the communication setting process at step LS225, itis determined whether the level of the fifth contact 204 e(Fmax1/Inverse-FBL) is a high level (step LS227). If the level of thefifth contact 204 e (Fmax1/Inverse-FBL) is not a high level (if NO stepLS227), the operation at step LS227 is performed again, so that theoperation at step LS227 is repeated until the level of the fifth contact204 e (Fmax1/Inverse-FBL) rises to a high level. If the level of thefifth contact 204 e (Fmax1/Inverse-FBL) is a high level (if YES stepLS227), the sixth contact 204 f (Fmax2/Inverse-FLB) is raised to a highlevel (step LS229), and subsequently control returns.

A 1 ms-timer interrupt process for the image-shake compensationoperation will be hereinafter discussed in detail with reference to theflow chart shown in FIG. 15. The 1 ms-timer interrupt process startseach time a 1 ms hard timer expires during operation of the lens CPU211. In the 1 ms-timer interrupt process, the lens CPU 211 inputs anangular speed signal from each of the X-direction angular speed sensor251 and the Y-direction angular speed sensor 252 to detect the vibrationof the photographing lens 200 due to hand movement, and subsequentlydetermines the direction of driving of the compensation lens LC and theamount of movement (speed) thereof to drive the X-motor 254 and theY-motor 257 to move the compensation lens LC by the determined amount ofmovement in the determined driving direction.

In the 1 ms-timer interrupt process, firstly it is determined whether acompensation function OFF flag is “1” (step LS301). If the compensationfunction OFF flag is “1” (if YES step LS301), a compensation work flagis set to “0” (step LS303) and control returns. The compensation workflag “1” or “0” indicates that the image-shake compensation deviceoperates or does not operate, respectively.

If the compensation function OFF flag is “0” (if NO step LS301), it isdetermined whether a compensation ON flag is “0” (step LS305). If thecompensation ON flag is “0” (if YES step LS305), this means that theimage-shake compensation operation is not performed, so that thecompensation work flag is set to “0” (step LS303), and control returns.

If the compensation ON flag is “1” (if NO step LS305), the compensationwork flag is set to “1”, and subsequently a vibration detection processis performed (step LS309). In the vibration detection process, the lensCPU inputs an angular speed signal from each of the X-direction angularspeed sensor 251 and the Y-direction angular speed sensor 252 to detectthe vibration of the photographing lens 200, and subsequently determinesthe direction of driving of the compensation lens LC and the amount ofmovement thereof.

After the vibration detection process at step LS309 is performed, it isdetermined whether a drive ON flag is “0” (step LS311). If the drive ONflag is not “0” (if NO at step LS311), the X-motor 254 and the Y-motor257 are driven to move the compensation lens LC by the amount ofmovement in the determined driving direction that are determined at stepLS309 (step LS315), and subsequently control returns. If the drive ONflag is “0” (if YES at step LS311), the driving of each of the X-motor254 and the Y-motor 257 is stopped forcefully (step LS313), and controlreturns.

An inverse-INT interrupt process will be hereinafter discussed withreference to the flow chart shown in FIGS. 16 and 17. The inverse-INTinterrupt process starts immediately after the level of the fifthcontact 204 e (Fmax1/Inverse-FBL) falls to a low level to thereby causethe port (inverse) INT of the lens CPU 211 to fall to a low level.

In the inverse-INT interrupt process, firstly at least one command isreceived from the camera body 100 via the new-type communication (stepLS401). Subsequently, it is determined whether at least one of commands70, 71 and 72 was received at step LS401 (step LS403). If at least oneof commands 70, 71 and 72 was received at step LS401 (if YES at stepLS403), a lens data transmitting process (8-bit data transmittingprocess) is performed via the new-type communication (step LS405), andcontrol proceeds to step LS407. If none of commands 70, 71 and 72 wasreceived at step LS401 (if NO at step LS403), control proceeds straightfrom step LS403 to step LS407.

At step LS407, it is determined whether at least one of commands B0 andB1 was received at step LS401. If neither of commands B0 and B1 wasreceived at step LS401 (if NO at step LS407), control proceeds to stepLS431. If at least one of commands B0 and B1 was received at step LS401(if YES at step LS407), a body data receiving process is performed viathe new-type communication (step LS409). Subsequently, it is determinedwhether the main switch flag SWMAIN has changed from “0” to “1” (stepLS411), whether the main switch flag SWMAIN has changed from “1” to “0”(step LS415), whether the power hold flag PH is “1” (step LS419), andwhether the power hold flag PH has changed from “1” to “0” (step LS423).

If it is determined at step LS411 that the main switch flag SWMAIN haschanged from “0” to “1” (if YES at step LS411), the compensation lensreset flag is set to “1” (step LS413), and control proceeds to stepLS415. If it is determined at step LS415 the main switch flag SWMAIN haschanged from “1” to “0” (if YES at step LS415), the compensation lenscenter flag is set to “1” (step LS417), and control proceeds to stepLS419. If it is determined at step LS419 that the power hold flag PH is“1” (if YES at step LS419), the compensation ON flag is set to “1” (stepLS421), and control proceeds to step LS423. If it is determined at stepLS423 that the power hold flag PH has changed from “1” to “0” (if YES atstep LS423), the compensation ON flag is set to “0” and the compensationlens center flag is set to “1” (step LS424), and control proceeds tostep LS425. If it is determined “NO” at all of steps LS411, LS415, LS419and LS423, control proceeds from step LS411 to step LS425 with none ofthe operations at steps LS413, LS417, LS421 and LS424 being performed.

At step LS425, it is determined whether the flag PAUSE is “1”. If theflag PAUSE is “1” (if YES at step LS425), the drive ON flag is set to“0” (step LS427), and control proceeds to step LS431. If the flag PAUSEis “0” (if NO at step LS425), the drive ON flag is set to “1” (stepLS429), and control proceeds to step LS431. The flag PAUSE is set to “1”when any high power operation which requires a large current iscurrently performed. In the present embodiment of the SLR camera system,the flag PAUSE is set to “1” when the electronic flash is in the middleof charging (step CS311). Subsequently, the lens CPU 211 sets the driveON flag to “0” upon receipt of the flag PAUSE “1” (step LS427), andcontrol proceeds from step LS311 to step LS313 to stop the driving ofeach of the X-motor 254 and the Y-motor 257 forcefully in the 1 ms-timerinterrupt process shown in FIG. 15. However, the X-direction angularspeed sensor 251 and the Y-direction angular speed sensor 252 continueto operate.

It is determined at step LS431 whether at least one of commands 71 andB1 was received at step LS401. If at least one of commands 71 and B1 wasreceived at step LS401 (if YES at step LS431), the sleep flag is set to“1” (step LS433), and control proceeds to step LS435. If neither ofcommands 71 and B1 was received at step LS401 (if NO at step LS431),control proceeds from step LS431 to step LS435. If the sleep flag is setto “1”, control proceeds from step LS105 to step LS107 so that the lensCPU 211 enters the sleep mode in the main process shown in FIG. 13.

Command 71 is data which is transmitted from the camera body 100 to thephotographing lens 200 to make the photographing lens 200 send thestatus thereof to the camera body 100, and also to make the lens CPU 211enter a sleep mode together with the body CPU 111.

At step LS435, it is determined whether command D0 was received at stepLS401. If command D0 was received at step LS401 (if YES at step LS435),the sleep flag is set to “1” (step LS437), and control proceeds to stepLS439. If command D0 was not received at step LS401 (if NO at stepLS435), control proceeds straight from step LS435 to step LS439.

At step LS439, it is determined whether command D1 was received at stepLS401. If command D1 was received at step LS401 (if YES at step LS439),the compensation function OFF flag is set to “1” (step LS441), andcontrol proceeds to step LS443. If command D1 was not received at stepLS401 (if NO at step LS439), control proceeds straight from step LS439to step LS443.

At step LS443 it is determined whether command D2 was received at stepLS401. If command D2 was received at step LS401 (if YES at step LS443),the compensation function OFF flag is set to “0” (step LS445), andcontrol proceeds to step LS447. If command D2 was not received at stepLS401 (if NO at step LS443), control proceeds straight from step LS443to step LS447.

At step LS447 it is determined whether command was received at stepLS401. If command 7F was received at step LS401 (if YES at step LS447),the lens CPU 211 performs a dummy data communication process (stepLS449) and control returns. If command 7F was not received at step LS401(if NO at step LS447), control returns.

Command 7F is data which is transmitted from the camera body 100 to thephotographing lens 200 to make the rear converter 300 output datatherefrom, if the rear converter 300 is mounted between the camera body100 and the photographing lens 200. The dummy data communication processat step LS449 is performed to allocate communication channel for thebody CPU 111 so that the body CPU 111 can receive data output from therear converter 300.

Fundamental structures and processes of an embodiment of thephotographing lens 200 which incorporates an image-shake compensationdevice have been described above. Another embodiment (second embodiment)of the photographing lens 200 which incorporates a lens AF system willbe hereinafter discussed with reference to FIGS. 22 through 26. Itshould be noted that elements and processes/processes in the secondembodiment of the photographing lens 200 which are similar to those inthe first embodiment of the photographing lens 200 shown in FIGS. 12through 17 are respectively designated by similar reference numerals andstep numbers.

FIG. 22 is a block diagram of fundamental elements of acommunication/control system of the second embodiment of thephotographing lens 200 which incorporates a lens AF system. The secondembodiment of the photographing lens 200 is provided with an AF motordriver 261, an AF motor (lens motor) 262 and a photo-interrupter 263.The lens CPU 211 drives the AF motor 262 via the AF motor driver 261 inaccordance with data on the driving-amount of the AF motor 262 and thedriving direction thereof that is received from the body CPU 111 to movea focusing lens group Lf along the optical axis thereof to an axialposition thereon at which an in-focus state is obtained. The amount ofmovement of the focusing lens group Lf is detected by counting thenumber of pulses output from the photo-interrupter 263.

FIG. 23 shows a flow chart for the main process of the second embodimentof the photographing lens 200 which incorporates a lens AF system.Control enters the main process immediately after the lens CPU 211 issupplied with power via the operation at step CS225, at which power issupplied to the power contact 105 (VPZ).

In the main process shown in FIG. 23, firstly the lens CPU 211initializes internal RAM and ports thereof (step LS101). Subsequently,the new-type communication setting process (“new-type communicationsetting process” shown in FIG. 14) is performed (step LS103). In thisprocess, a 1 ms-timer interrupt (see FIG. 24) and an interrupt via theport (inverse) INT of the lens CPU 211 (see FIG. 25) are enabled toreceive an interrupt from the camera body 100 to thereby make thenew-type communication possible between the photographing lens 200 andthe camera body 100.

Subsequently, it is determined whether a sleep flag which is set to “1”at step LS433 or LS437 is “1” (step LS105). If the sleep flag is “1” (ifYES at step LS105), the lens CPU 211 stops internal devices of thephotographing lens 200 such as the AF motor 262 and thephoto-interrupter 263 (step LS107), the sleep flag is set to “0” (stepLS109), and the lens CPU 211 enters the sleep mode (step LS111). Thelens CPU 211 wakes up on receiving an interrupt signal via the port(inverse) INT thereof.

If it is determined at step CS105 that the sleep flag is not “1” (if NOat step LS105), the operation at step LS105 is repeated. The new-typecommunication setting process shown in FIG. 14, a 1 ms-timer interruptprocess shown in FIG. 24, and an inverse-INT interrupt process shown inFIG. 25 are performed during the time the operation at step LS105 isrepeated.

The new-type communication setting process performed at step LS103 shownin FIG. 23 is identical to that shown in FIG. 14, and accordinglyfurther description of the new-type communication setting processperformed at step LS103 shown in FIG. 23 is omitted.

The 1 ms-timer interrupt process which is repeated at regular intervalswhen the lens CPU 211 is in operation, in the second embodiment of thephotographing lens 200, will be hereinafter discussed with reference tothe flow chart shown in FIG. 24. This 1 ms-timer interrupt processstarts each time a 1 ms hard timer expires during operation of the lensCPU 211 to control operation of the AF motor 262.

In the 1 ms-timer interrupt process, firstly it is determined whether anAF function ON flag is “0” (step LS331). If the AF function ON flag is“0” (if YES step LS331), a lens AF process is not performed, wherein anAF work flag is set to “0” (step LS333), and control returns. The AFwork flag “1” or “0” indicates that the lens AF process operates or doesnot operate, respectively.

If the AF function ON flag is not “0” (if NO step LS331), it isdetermined whether a drive end flag is “1” (step LS335). If the driveend flag is “1” (if YES at step LS335), this means that the driving ofthe AF motor 262 has been completed, so that the AF work flag is set to“0” (step LS333) and control returns.

If the drive end flag is not “1” (if NO at step LS335), it is determinedwhether a drive ON flag is “0” (step LS337). If the drive ON flag is “0”(if YES at step LS337), the AF motor 262 is stopped forcefully (stepLS339), and control returns.

If the drive ON flag is not “0” (if NO at step LS337), the AF work flagis set to “1” (step LS341), and subsequently the AF motor 343 is started(driven) (step LS343). Subsequently, it is determined whether thedriving of the AF motor 343 is completed (step LS345). If the driving ofthe AF motor 343 is completed (if YES at step LS345), the drive end flagis set to “1” (step LS347), and control returns. If the driving of theAF motor 343 has not been completed (if NO at step LS345), controlreturns.

An inverse-INT interrupt process in the second embodiment of thephotographing lens 200 will be hereinafter discussed with reference tothe flow chart shown in FIGS. 25 and 26. The inverse-INT interruptprocess starts immediately after the level of the fifth contact 204 e(Fmax1/Inverse-FBL) falls to a low level to thereby cause the port(inverse) INT of the lens CPU 211 to fall to a low level.

In the inverse-INT interrupt process, firstly at least one command isreceived from the camera body 100 via the new-type communication (stepLS401). Subsequently, it is determined whether at least one of commands70, 71 and 72 was received at step LS401 (step LS403). If at least oneof commands 70, 71 and 72 was received at step LS401 (if YES at stepLS403), a lens data transmitting process (8-bit data transmittingprocess) is performed via the new-type communication, and controlproceeds to step LS407. If none of commands 70, 71 and 72 was receivedat step LS401 (if NO at step LS403), control proceeds straight from stepLS403 to step LS407.

At step LS407, it is determined whether at least one of commands B0 andB1 was received at step LS401. If neither of commands B0 and B1 wasreceived at step LS401 (if NO at step LS407), control proceeds to stepLS461. If at least one of commands B0 and B1 was received at step LS401(if YES at step LS407), a body data receiving process is performed viathe new-type communication (step LS409). Subsequently, it is determinedwhether the AF ON flag is “1” (step LS451). If the AF ON flag is “1”,(if YES at step LS451), the AF function ON flag is set to “1” (stepLS453), and control proceeds to step LS455. If the AFON flag is not “1”,(if NO at step LS451), the AF function ON flag is set to “0” (stepLS454), and control proceeds to step LS455.

At step LS455 it is determined whether the release stage indicator RLSis “2”. The release stage indicator RLS is a two-bit data which is setto “0”, “1”, “2” or “3” by the body CPU 111. The release stage indicatorRLS “1” indicates a stage at which the quick return mirror is movingtoward the retracted position thereof after the release switch SWR hasbeen turned ON. The release stage indicator RLS “2” indicates a stage atwhich a film frame is under exposure after the quick return mirror hasmoved up to the retracted position thereof. The release stage indicatorRLS “3” indicates a stage at which the camera body 100 is in a stage atwhich film is advanced after the exposure operation has been completed.The release stage indicator RLS “0” indicates any other stage of thecamera body 100. If the release stage indicator RLS is “2” (if YES atstep LS455), this means that a film frame is under exposure after thequick return mirror has moved up to the retracted position thereof, sothat the drive ON flag is set to “0” (step LS457), and control proceedsto step LS461. If the release stage indicator RLS is not “2” (if NO atstep LS455), the drive ON flag is set to “1” (step LS459) and controlproceeds to step LS461.

At step LS461, it is determined whether command B2 was received at stepLS401. If command B2 was received at step LS401 (if YES at step LS461),lens driving amount data is received from the body CPU 111 (step LS463).Subsequently, this received lens driving amount data is set (stepLS465), and the drive end flag is set to “0” (step LS467). Subsequently,control proceeds to step LS431. If command B2 was not received at stepLS401 (if NO at step LS461), control proceeds to step LS431.

It is determined at step LS431 whether at least one of commands 71 andB1 was received at step LS401. If at least one of commands 71 and B1 wasreceived at step LS401 (if YES at step LS431), the sleep flag is set to“1” (step LS433) and control proceeds to step LS435. If neither ofcommands 71 and B1 was received at step LS401 (if NO at step LS431),control proceeds from step LS431 to step LS435. If the sleep flag is setto “1”, control proceeds from step LS105 to step LS107, in the mainprocess shown in FIG. 13, so that the lens CPU 211 enters the sleepmode.

At step LS435, it is determined whether command D0 was received at stepLS401. If command D0 was received at step LS401 (if YES at step LS435),the sleep flag is set to “1” (step LS437) and control proceeds to stepLS469. If command D0 was not received at step LS401 (if NO at stepLS435), control proceeds straight from step LS435 to step LS469.

At step LS469, it is determined whether command D3 was received at stepLS401. If command D3 was received at step LS401 (if YES at step LS469),the drive ON flag is set to “0” (step LS471), and control proceeds tostep LS473. If command D3 was not received at step LS401 (if NO at stepLS469), control proceeds straight from step LS469 to step LS473.

At step LS473, it is determined whether command D4 was received at stepLS401. If command D4 was received at step LS401 (if YES at step LS473),the drive ON flag is set to “1” (step LS475), and control proceeds tostep LS477. If command D4 was not received at step LS401 (if NO at stepLS473), control proceeds straight from step LS473 to step LS477.

At step LS477 it is determined whether command 7F was received at stepLS401. If command 7F was received at step LS401 (if YES at step LS447),the lens CPU 211 performs the dummy data communication process (stepLS479), and control returns. If command 7F was not received at stepLS401 (if NO at step LS477), control returns. At this point, command 7Fis issued for data communication between the lens CPU 211 and a CPU(controller/rear converter controller) 311 of the rear converter 300. Ina state where the rear converter 300 is mounted between the camera body100 and the photographing lens 200, the CPU 311 of the rear converter300 recognizes command 7F as a command for the rear converter 300 uponreceipt of command 7F, and subsequently sends rear convertercommunication data (new-type communication data) to the body CPU 111.

FIG. 27 is a schematic block diagram of fundamental elements of controlsystems of the photographing lens 200, the rear converter 300, and thecamera body 100 of an embodiment of the SLR camera system according tothe present invention, wherein the rear converter 300 is mounted betweenthe camera body 100 and the photographing lens 200. The rear converter300 is provided with the CPU 311 serving as a controller which controlsfunctions of the rear converter 300, and the ROM 321 serving as astoring device in which fundamental data on the rear converter 300 arestored. As shown in FIG. 27, each of the CPU 311 and the ROM 321 of therear converter 300 is provided with I/O ports similar to those of thelens CPU 211 and the lens ROM 221. The rear converter 300 can eitherserve as a teleconverter or wide converter, being provided with avariable power lens group (not shown).

The rear converter 300 is provided with a rear mount 303 which ismounted to the mount 103 of the camera body 100, and a front mount 3031to which the lens mount 203 of the photographing lens 200 is mounted.The rear mount 303 is provided thereon with six contacts(relay/communication contacts) which come in contact with the sixcontacts 104 a through 104 f provided on the mount 103 of the camerabody 100, respectively, while the front mount 3031 is provided thereonwith another six contacts (relay/communication contacts) which come incontact with the six contacts 204 a through 204 f provided on the lensmount 203 of the photographing lens 200.

The six contacts formed on the rear mount 303 of the rear converter 300include a first contact 304 a (Fmin1/Inverse-SCKL), a second contact 304b (Fmin2/DATAL), a third contact 304 c (Fmin3/RESL), a fourth contact304 d (CONTL), a fifth contact 304 e (Fmax1/Inverse-FBL), and a sixthcontact 304 f (Fmax2/Inverse-FLB). The six contacts formed on the frontmount 3031 of the rear converter 300 include a first contact 304 a 1(Fmin1/Inverse-SCKL), a second contact 304 b 1 (Fmin2/DATAL), a thirdcontact 304 c 1 (Fmin3/RESL), a fourth contact 304 d 1 (CONTL), a fifthcontact 304 e 1 (Fmax1/Inverse-FBL), and a sixth contact 304 f 1(Fmax2/Inverse-FLB) which are connected with the first contact 304 a(Fmin1/Inverse-SCKL), the second contact 304 b (Fmin2/DATAL), the thirdcontact 304 c (Fmin3/RESL), the fourth contact 304 d (CONTL), the fifthcontact 304 e (Fmax1/Inverse-FBL), and the sixth contact 304 f(Fmax2/Inverse-FLB) on the rear mount 303, respectively. Accordingly,the rear six contacts 304 a through 304 f and the front six contacts 304a 1 through 304 f 1 of the rear converter 300 serve as a group of relaychannels via which the group of communication/control contacts 104 (104a through 104 f) on the mount 103 of the camera body 100 areelectrically connected with the group of communication/control contacts204 (204 a through 204 f) on the lens mount 203 of the photographinglens 200, respectively, in a state where the rear converter 300 isproperly mounted between the camera body 100 and the photographing lens200.

The first contact 304 a (Fmin1/Inverse-SCKL) on the rear mount 303 andthe first contact 304 a 1 (Fmin1/Inverse-SCKL) on the front mount 3031are connected to a port Inverse-SCK of each of the CPU 311 and the lensROM 321. The second contact 304 b (Fmin2/DATAL) on the rear mount 303and the second contact 304 b 1 (Fmin2/DATAL) on the front mount 3031 areconnected to a port DATA of each of the CPU 311 and the lens ROM 321.The third contact 304 c (Fmin3/RESL) on the rear mount 303 and the thirdcontact 304 c 1 (Fmin3/RESL) on the front mount 3031 are connected to aport RES of each of the CPU 311 and the lens ROM 321. The fourth contact304 d (CONTL) on the rear mount 303 and the fourth contact 304 d 1(CONTL) on the front mount 3031 are connected to a port CONT of each ofthe CPU 311 and the lens ROM 321. The fifth contact 304 e(Fmax1/Inverse-FBL) on the rear mount 303 and the fifth contact 304 e 1(Fmax1/Inverse-FBL) on the front mount 3031 are connected to a port(Fmax/Inverse-FBL) of each of the CPU 311 and the lens ROM 321. Thesixth contact 304 f (Fmax2/Inverse-FLB) on the rear mount 303 and thesixth contact 304 f 1 (Fmax2/Inverse-FLB) on the front mount 3031 arenot connected to any ports of each of the CPU 311 and the lens ROM 321.

The CPU 311 of the rear converter 300 is not provided with any portwhich corresponds to a connection port of the lens CPU 211 that isconnected to the sixth contact 204 f (Fmax2/Inverse-FLB) on the lensmount 203. The lens CPU 211 starts communicating with the body CPU 111immediately after the level of the fifth contacts 104 e and 204 e(Fmax1/Inverse-FBL) fall to a low level, and a handshake operation isperformed between the body CPU 111 and the lens CPU 211 via the sixthcontacts 104 f and 204 f (Fmax2/Inverse-FLB). While the handshakeoperation is performed, the CPU 311 sends out data (rear converter data)on the rear converter 300 via a port Fmax1 of the CPU 311 insynchronization with signals transmitted through the fifth contacts 104e and 204 e (Fmax1/Inverse-FBL). For this reason, the CPU 311 isprovided with no port which is connected to the sixth contacts 104 f and204 f (Fmax2/Inverse-FLB) which are used for the handshake performedbetween the body CPU 111 and the lens CPU 211. The fifth contact 304 e(Fmax1/Inverse-FBL) on the rear mount 303 is connected to a firstcommunication/control contact. The first communication/control contactis defined by the fifth contacts 104 e and 204 e.

The rear converter 300 is provided on the rear mount 303 thereof with apower contact 305, and is provided on the front mount 3031 thereof witha power contact 3051. The power contact 105 of the camera body 100 isconnected with the power contact 205 of the photographing lens 200 viathe two power contacts 305 and 3051 when the rear converter 300 ismounted between the camera body 100 and the photographing lens 200.Battery power can be supplied to the CPU 311 from the battery 113 viathe power contacts 105 and 205. Likewise, battery power can be suppliedto the lens CPU 211 from the battery 113 via the power contacts 305 and3051.

The rear converter 300 is characterized in that the CPU 311 thereofsends out data on the rear converter 300 on demand of the body CPU 111while the handshake operation is performed between the body CPU 111 andthe lens CPU 211.

Fundamental operations of the embodiment of the SLR camera system withthe rear converter 300 will be hereinafter discussed in detail withreference to the timing charts shown in FIGS. 28 and 29 in combinationwith the flow charts shown in FIGS. 30, 31 and 32. Operations forcommunications between the camera body 100 and the photographing lens200 are to the same as those in the above-described embodiment of theSLR camera system wherein the rear converter 300 is not mounted betweenthe camera body 100 and the photographing lens 200.

Immediately after the main switch SWMAIN is turned ON in a state wherethe rear converter 300 is properly mounted between the camera body 100and the photographing lens 200, as shown in FIG. 27, the body CPU 111supplies the first power to the fourth contact 104 d (CONTL), and makesthe level of the third contact 104 c (Fmin3/RESL) fall to a low level tocommunicate with the lens ROM 221, i.e., to perform the lens ROMcommunication (the old-type communication). At this time, the firstpower is supplied to each of the CPU 311 and the ROM 321 of the rearconverter 300 via the fourth contact 304 d (CONTL), while the lens ROM221 is set to change from a disable state to an enable state if thelevel of the third contact 304 c (Fmin3/RESL) falls to a low level.

Although this old-type communication is similar to the old-typecommunication performed with no rear converter being mounted between thecamera body 100 and the photographing lens 200, the lens ROM 221 doesnot output any data for the last few bytes when sending out the lensdata on the photographing lens 200, rather, the ROM 321 of the rearconverter 300 outputs data on the rear converter 300 (rear converterdata) instead. The rear converter data that is output from the ROM 321of the rear converter 300 is, e.g., data on the type of the rearconverter 300, so that the body CPU 111 recognizes the existence of therear converter 300 upon receiving the rear converter data. Subsequently,if the body CPU 111 recognizes the rear converter 300 as a new typewhich is compatible with the new-type lens communication, the body CPU111 issues command 7F to the rear converter 300 to communicate with theCPU 311 of the rear converter 300 to receive the aforementioned rearconverter communication data (new-type communication data) from the CPU311. Since the rear converter communication data is transmitted to thebody CPU 111 under control of the CPU 311 of the rear converter 300,data values in the rear converter communication data can be varied inaccordance with a variation in power of the rear converter 300, and/orthe rear converter communication data can be sent out with additionalinformation. This increases the degree of freedom in the development ofthe rear converter 300.

FIG. 30 shows a flow chart for the main process of the rear converter300 which is performed by the CPU 311 thereof. Control enters the mainprocess shown in FIG. 30 immediately after the level of the fifthcontact 304 e (Fmax1/Inverse-FBL) falls to a low level and the level ofthe third contact 304 c (Fmin3/RESL) rises to a high level when the bodyCPU 111 supplies the first power to the fourth contact 304 d (CONTL). Itshould be noted that operations or processes having step numbers bearinga prefix “RS” are related to control/operation of the rear converter300.

In the main process shown in FIG. 30, firstly the CPU 311 of the rearconverter 300 initializes internal RAM and ports thereof (step RS101).Subsequently, a new-type communication setting process (“new-typecommunication setting process” shown in FIG. 31) is performed (stepRS103). In this process, an interrupt via an interrupt port Fmax1(inverse-INT) of the CPU 311 is enabled to receive an interrupt from thecamera body 100 to thereby make the new-type communication possiblebetween the camera body 100 and the rear converter 300.

Subsequently, it is determined whether a sleep flag which is set to “1”by a command issued by the body CPU 111 is “1” (step RS105). If thesleep flag is “1” (if YES at step RS105), the CPU 311 performs a CPUstop operation to enter a power saving mode (step RS107), the sleep flagis set to “0” (step RS109), and the CPU 311 enters sleep mode (stepRS111). The CPU 311 wakes upon receiving an interrupt signal via theinterrupt port Fmax1 (inverse-INT) of the CPU 311.

If it is determined at step RS105 that the sleep flag is not “1” (if NOat step RS105), the operation at step RS105 is repeated. The new-typecommunication setting process shown in FIG. 31 is performed during thetime the sleep flag (which is checked at step RS105) is “0”.

The new-type communication setting process performed at step RS103 willbe hereinafter discussed in detail with reference to the flow chartshown in FIG. 31. In the new-type communication setting process, firstlyit is determined whether the level of the interrupt port Fmax1(inverse-INT) is a low level (step RS201). If the level of the interruptport Fmax1 (inverse-INT) is not a low level (if NO step RS201), theoperation at step RS201 is performed again, so that the operation atstep RS201 is repeated until the level of the interrupt port Fmax1(inverse-INT) falls to a low level. If the level of the interrupt portFmax1 (inverse-INT) falls to a low level (if YES step RS201), acommunication setting process is performed (step RS203). Thecommunication setting process includes a setting process for serialcommunication, and an interrupt enabling process via the interrupt portFmax1 (inverse-INT). Upon completion of the communication settingprocess at step RS203, it is determined whether the level of theinterrupt port Fmax1 (inverse-INT) is a high level (step RS205). If thelevel of the interrupt port Fmax1 (inverse-INT) is not a high level (ifNO step RS205), the operation at step RS205 is performed again, so thatthe operation at step RS205 is repeated until the level of interruptport Fmax1 (inverse-INT) rises to a high level. Control returns if thelevel of interrupt port Fmax1 (inverse-INT) rises to a high level (ifYES step RS205).

The inverse-INT interrupt process performed by the CPU 311 of the rearconverter 300 will be hereinafter discussed with reference to the flowchart shown in FIG. 32. The inverse-INT interrupt process shown in FIG.32 starts immediately after the level of the fifth contact 304 e(Fmax1/Inverse-FBL) falls to a low level to thereby cause the interruptport Fmax1 (inverse-INT) of the CPU 311 to fall to a low level. In theinverse-INT interrupt process shown in FIG. 32, the CPU 311 sends therear converter data to the camera body 100 upon receipt of command 7F.

In the inverse-INT interrupt process shown in FIG. 32, firstly at leastone command (8-bit data) is received from the camera body 100 via thenew-type communication (step RS301). Subsequently, it is determinedwhether at least one of commands 70, 71, 72, B0, B1, B2, D1, D2, D3 andD4 was received at step RS301 (step RS303). If at least one of thesecommands was received at step RS301 (if YES at step RS303), such acommand or commands are those which have been issued for thephotographing lens 200, so that a dummy data communication process inwhich the CPU 311 receives unnecessary communication data (dummy data)for the rear converter 300 is performed (step RS305), and subsequentlycontrol proceeds to step RS307. If none of commands 70, 71, 72, B0, B1,B2, D1, D2, D3 and D4 is received at step RS301 (if NO at step RS303),control proceeds from step RS303 to step RS307.

At step RS307, it is determined whether at least one of commands D0, 71and B1 was received at step RS301. If at least one of commands D0, 71and B1 was received at step RS301 (if YES at step RS307), the sleep flagis set to “1” (step RS309), and control proceeds to step RS311. If noneof commands D0, 71 and B1 was received at step RS301 (if NO at stepRS307), control proceeds from step RS307 to step RS311. Accordingly,when the photographing lens 200 enters sleep mode, the rear converter300 also enters sleep mode.

At step RS311 it is determined whether command 7F was received at stepRS301. If command 7F was received at step RS301 (if YES at step RS311),the rear converter data is transmitted to the body CPU 311 (step RS313)and subsequently control returns. If it is determined at step RS311 thatcommand 7F was not received at step RS301 (if NO at step RS311), controlreturns. Command 7F is issued for the rear converter 300. Thephotographing lens 200 performs the dummy data communication process(step LS449 or LS479) upon receiving command 7F issued by the body CPU111, and the CPU 311 of the rear converter 300 sends the rear converterdata to the body CPU 111 in synchronization with the dummy datacommunication process. The body CPU 111 performs operations/processes inaccordance with the rear converter data upon receiving the rearconverter data.

As can be understood from the above descriptions, according to thepresent embodiment of the SLR camera system to which the presentinvention is applied, a data area for the rear converter 300 is securedin advance so that the rear converter 300 can send the rear converterdata to the camera body during data communication between the camerabody 100 and the photographing lens 200. This makes it possible for thecamera body 100 to communicate with each of the photographing lens 200and the rear converter 300, and to control operations of thephotographing lens 200 and the rear converter 300 without the need forswitching data communications therebetween.

The rear converter can be provided with one or more additionalfunctions/capabilities, e.g., a variable diaphragm function and aswing/tilt function. If the rear converter is provided with such one ormore additional functions/capabilities, data on such additionalfunctions/capabilities can be transmitted to the camera body as the rearconverter data.

As can be understood from the foregoing, according to the presentembodiment of the SLR camera system to which the present invention isapplied, since the rear converter includes a group of relay channels viawhich the first group of contacts of the camera body are electricallyconnected with the second group of contacts of the photographing lens,respectively, in a state where the rear converter is properly mountedbetween the camera body and the photographing lens; a memory in whichrear converter data on the rear converter is stored, the memoryincluding at least one port electrically connected to corresponding atleast one relay channel of the group of relay channels; and a controllerwhich controls a reading operation of the rear converter data from thememory, the controller including at least one port electricallyconnected to corresponding at least one relay channel of the group ofrelay channels; wherein the memory and the controller have a function tosend the rear converter data to the camera body while the camera bodyand the photographing lens communicate with each other via the firstgroup of contacts, the second group of contacts, and the group of relaychannels; neither the camera body nor the photographing lens needs to beprovided with any additional contacts for data communications. Inaddition, data on the rear converter can be transmitted to the camerabody without the need for switching in data communications between thephotographing lens and the rear converter.

Obvious changes may be made in the specific embodiments of the presentinvention described herein, such modifications being within the spiritand scope of the invention claimed. It is indicated that all mattercontained herein is illustrative and does not limit the scope of thepresent invention.

What is claimed is:
 1. An interchangeable lens camera system having acamera body, a photographing lens, and a rear converter which can bemounted between said camera body and said photographing lens, saidcamera body having a first group of contacts, said photographing lenshaving a second group of contacts, said camera body and saidphotographing lens communicating with each other via said first group ofcontacts and said second group of contacts with said first group ofcontacts being electrically connected with said second group ofcontacts, respectively, wherein said rear converter comprises: a groupof relay channels via which said first group of contacts of said camerabody are electrically connected with said second group of contacts ofsaid photographing lens, respectively, in a state where said rearconverter is mounted between said camera body and said photographinglens; a rear converter memory in which rear converter data on said rearconverter is stored, said rear converter memory including at least oneport electrically connected to corresponding at least one relay channelof said group of relay channels; and a rear converter controller whichcontrols a reading operation of said rear converter data from said rearconverter memory, said rear converter controller including at least oneport electrically connected to corresponding at least one relay channelof said group of relay channels, wherein said rear converter memory andsaid rear converter controller have a function to send said rearconverter data to said camera body while said camera body and saidphotographing lens communicate with each other via said first group ofcontacts, said second group of contacts, and said group of relaychannels, wherein said camera body comprises a body controller thatcommunicates with a lens memory of said photographing lens to readphotographing lens data from said lens memory, a portion of saidphotographing lens data serving as dummy data for said rear converter,said rear converter data being read out of said rear converter memory tobe transmitted to said body controller in synchronization with anoperation of said body controller in which said body controller receivessaid dummy data.
 2. The interchangeable lens camera system according toclaim 1, wherein said body controller is electrically connected to saidrear converter controller via a first communication/control contact ofeach of said first group of contacts and said second group of contacts,and a data I/O contact of each of said first group of contacts and saidsecond group of contacts; wherein said photographing lens includes alens controller which communicates with said body controller; andwherein said body controller is electrically connected to said lenscontroller via said first communication/control contact, a secondcommunication/control contact of each of said first group of contactsand said second group of contacts, and at least one relay channel ofsaid group of relay channels, wherein a handshake operation is performedbetween said body controller and said lens controller via said secondcommunication/control contact.
 3. The interchangeable lens camera systemaccording to claim 2, wherein said lens controller sends out dummy datato enable said data I/O contact if inputting a command for said rearconverter, which is issued by said body controller, via said data I/Ocontact, while said lens controller communicates with said bodycontroller; and wherein said rear converter sends out said rearconverter data to said data I/O contact in the case where said commandis input via said data I/O contact.
 4. The interchangeable lens camerasystem according to claim 3, wherein said rear converter receives saiddummy data from said lens controller in the case where said lenscontroller receives said command; and wherein said rear converter sendssaid rear converter data to said body controller in synchronization withan operation of said body controller in which said body controllerreceives said dummy data.
 5. The interchangeable lens camera system ofclaim 3, wherein said rear converter receives said dummy data from saidlens controller in the case where said lens controller receives saidcommand, said rear converter sending said rear converter data to saidbody controller in synchronization with an operation of said bodycontroller in which said body controller receives said dummy data. 6.The interchangeable lens camera system according to claim 1, whereinsaid body controller is set to recognize one of a last one byte and alast few types of said photographing lens data as said dummy data forsaid rear converter.
 7. A rear converter which can be mounted between acamera body and a photographing lens of an interchangeable lens camerasystem, said camera body having a first group of contacts, saidphotographing lens having a second group of contacts, said camera bodyand said photographing lens communicating with each other via said firstgroup of contacts and said second group of contacts with said firstgroup of contacts being electrically connected to said second group orcontacts, respectively, wherein said rear converter comprises: a groupof relay channels via which said first group of contacts of said camerabody are electrically connected with said second group of contacts ofsaid photographing lens, respectively, in a state where said rearconverter is mounted between said camera body and said photographinglens; a rear converter memory in which rear converter data is stored,said rear converter memory including ports electrically connected to atleast one relay channel of said group of relay channels; and a rearconverter controller which controls a reading operation of said rearconverter data from said rear converter memory, said rear convertercontroller including ports electrically connected to at least one relaychannel of said group of relay channels; wherein said rear convertermemory and said rear converter controller have a function to send saidrear converter data to said camera body while said camera body and saidphotographing lens communicate with each other via said first group ofcontacts, said second group of contacts, and said group of relaychannels, wherein said camera body comprises a body controller thatcommunicates with a lens memory of said photographing lens to readphotographing lens data from said lens memory, a portion of saidphotographing lens data serving as dummy data for said rear converter,said rear converter data being read out of said rear converter memory tobe transmitted to said body controller in synchronization with anoperation of said body controller in which said body controller receivessaid dummy data.
 8. The rear converter according to claim 7, whereineach of said first group of contacts and said second group of contactscomprises: a first communication/control contact via which said bodycontroller sends a control signal to said lens controller; a secondcommunication/control contact via which said lens controller sends acontrol signal to said body controller; and a data I/O contact for datacommunication; wherein said first communication/control contact, saidsecond communication/control contact, and said data I/O contact of saidfirst group of contacts are electrically connected to said firstcommunication/control contact, said second communication/control contactand said data I/O contact of said second group of contacts,respectively, via said group of relay channels; wherein said rearconverter memory and said rear converter controller are electricallyconnected to relay channels of said group of relay channels whichcorrespond to said first communication/control contact and said data I/Ocontact; and wherein said rear converter memory and said rear convertercontroller have a function to send said rear converter data to saidcamera body after a commencement of a handshake operation between saidbody controller and said lens controller via said secondcommunication/control contact in the case where said camera bodycommands said rear converter controller to send said rear converter datavia said data I/O contact.
 9. An interchangeable lens camera systemhaving a camera body, a photographing lens, and a rear converter whichcan be mounted between said camera body and said photographing lens,said camera body having a first group of contacts, said photographinglens having a second group of contacts, said camera body and saidphotographing lens communicating with each other via said first group ofcontacts and said second group of contacts with said first group ofcontacts being electrically connected with said second group ofcontacts, respectively, wherein said rear converter comprises: a groupof relay channels via which said first group of contacts of said camerabody are electrically connected with said second group of contacts ofsaid photographing lens, respectively, in a state where said rearconverter is mounted between said camera body and said photographinglens; a rear converter memory in which rear converter data on said rearconverter is stored, said rear converter memory including at least oneport electrically connected to corresponding at least one relay channelof said group of relay channels; and a rear converter controller whichcontrols a reading operation of said rear converter data from said rearconverter memory, said rear converter controller including at least oneport electrically connected to corresponding at least one relay channelof said group of relay channels, wherein said rear converter memory andsaid rear converter controller have a function to send said rearconverter data to said camera body while said camera body and saidphotographing lens communicate with each other via said first group ofcontacts, said second group of contacts, and said group of relaychannels, said lens controller sending out dummy data to enable saiddata I/O contact if inputting a command for said rear converter, whichis issued by said body controller, via said data I/O contact, while saidlens controller communicates with said body controller, said rearconverter sending out said rear converter data to said data I/O contactin the case where said command is input via said data I/O contact.